By 2025, AI is expected to handle over 95% of all customer interactions, and intelligent AI Voice Agents are at the forefront of this transformation. These are not the rigid, frustrating voice bots of the past. We're now in an era of conversational AI that can understand context, show empathy, and solve complex problems in real-time.

Many SaaS founders and developers recognize the potential of AI voice agents but are often unsure about the most impactful, ROI-driven applications. They need a clear roadmap that goes beyond the hype and provides actionable implementation strategies.

This deep dive will explore the most transformative AI voice agent use cases across key industries for 2025. We will not only show you what is possible but also provide a technical blueprint for how you can build and deploy these solutions using a low-latency, scalable infrastructure like VideoSDK.

What Are AI Voice Agents, and Why Are They Booming in 2025?

An AI voice agent is a sophisticated software program designed to understand and respond to human speech, enabling it to automate conversations and perform a wide range of tasks. Unlike traditional interactive voice response (IVR) systems that rely on rigid, pre-programmed menus, AI voice agents leverage artificial intelligence, machine learning (ML), and natural language processing (NLP) to engage in natural, human-like conversations. They can be integrated into various channels, including phone systems, mobile apps, and smart devices.

The boom in AI voice agents in 2025 is driven by several factors. Advances in AI have made them more capable and affordable to develop and deploy. Businesses are also facing increasing pressure to improve customer experience, reduce operational costs, and enhance efficiency, all of which AI voice agents can help address. The growing consumer comfort with voice-based interactions, fueled by the widespread adoption of smart speakers and voice assistants, has further accelerated this trend.

Recent data underscores this surge. With the AI market projected to contribute $15.7 trillion to the global economy by 2030, the adoption of AI-powered solutions is no longer a niche trend but a business imperative. This explosive growth is a clear indicator that AI voice agents are set to become a standard, rather than a novel, feature in customer interactions.

The Most Impactful AI Voice Agent Use Cases for 2025

AI voice agents are reshaping industries like BFSI, healthcare, retail, and logistics by automating customer interactions, enhancing personalization, and improving overall efficiency. Let's take a deep dive into specific use cases, practical implementation tips, and why real-time communication solutions like VideoSDK are the go-to choice for developers.

AI Voice Agents Revolutionizing Healthcare

The healthcare industry is ripe for disruption by AI voice agents, which can alleviate administrative burdens, improve patient engagement, and enhance the overall quality of care.

Intelligent Appointment Scheduling & Patient Intake

Problem: Medical receptionists are frequently overwhelmed by the sheer volume of calls for scheduling, rescheduling, and confirming appointments. This administrative bottleneck not only leads to long and frustrating wait times for patients but also contributes to staff burnout and a higher potential for human error in bookings.

Solution: An AI voice agent can automate the entire appointment management lifecycle, handling bookings, reminders, and cancellations 24/7 without human intervention. By also conducting initial patient intake to gather medical history and symptoms before the visit, these agents ensure healthcare staff are better prepared and the patient's time with the doctor is maximized. For such a system to be viable in healthcare, it must be built on a foundation of enterprise-grade security and support HIPAA compliance to protect sensitive patient data—a core tenet of robust communication platforms.

Post-Discharge Follow-up and Chronic Care Management

Problem: Ensuring patients adhere to post-operative care plans and effectively managing chronic conditions remotely are significant challenges for healthcare providers. Manual follow-up calls are time-consuming, difficult to scale, and often inconsistent, which can put patient recovery at risk.

Solution: AI voice agents can conduct automated follow-up calls to check on a patient's recovery, provide medication reminders, and monitor symptoms for chronic diseases. These agents can ask a series of questions to assess the patient's condition and, if any warning signs are detected, can escalate the case to a healthcare professional for immediate attention. To enable this, a platform with reliable real-time audio streaming and the capability to integrate sentiment analysis is key, allowing healthcare teams to personalize care while offloading repetitive tasks to compliant AI agents.

AI Voice Agents for Customer Service

Customer service is one of the most prominent areas where AI voice agents are making a significant impact, transforming how businesses support their customers.

First-Line Support for Common Queries

Problem: Customer support teams are often bogged down by a high volume of repetitive and straightforward inquiries, such as questions about order status, business hours, or basic product information. This diverts skilled human agents from addressing more complex customer issues, leading to longer wait times across the board.

Solution: AI voice agents can serve as the first line of support, handling a majority of these common queries instantly and 24/7. By automating responses to frequently asked questions, businesses can significantly reduce the workload on human agents and cut operational costs, allowing them to focus on resolving more sensitive customer issues. To effectively handle a high volume of concurrent calls, a robust and scalable infrastructure with a global network is essential for delivering clear, low-latency, and reliable customer interactions.

Smart Call Routing and Escalation

Problem: Misdirected calls are a common source of customer frustration and a major cause of inefficiency in contact centers. Traditional interactive voice response (IVR) systems are often rigid and confusing, leading to a poor customer experience and high call abandonment rates.

Solution: AI-powered smart call routing can analyze a customer's intent in real-time and direct them to the most appropriate agent or department. If the AI agent cannot resolve an issue, it can seamlessly escalate the call to a human agent, providing them with the full context of the conversation so the customer doesn't have to repeat themselves. A platform with flexible APIs allows for seamless integration with AI and machine learning models, enabling the development of sophisticated routing logic based on real-time data and sentiment analysis.

Post-Interaction Feedback & Sentiment Analysis

Problem: Gathering customer feedback is crucial for improving service quality, but traditional survey methods like emails often suffer from low response rates. It is also difficult to gauge the emotional tone of a customer interaction without the right tools, potentially leaving valuable insights on the table.

Solution: AI voice agents can automatically initiate post-interaction feedback calls or surveys, capturing insights while the experience is still fresh in the customer's mind. They can also perform real-time sentiment analysis during calls to gauge customer satisfaction and identify potential issues before they escalate. This requires a platform capable of capturing high-quality audio streams that can be fed into sentiment analysis engines and real-time transcription APIs to provide a textual record for deeper analysis.

AI Voice Agents in BFSI

In the banking, financial services, and insurance (BFSI) sector, AI voice agents are enhancing security, improving customer engagement, and automating routine processes.

Proactive Loan Servicing & EMI Reminders

Problem: Manually contacting thousands of customers for loan servicing and Equated Monthly Installment (EMI) reminders is a resource-intensive and repetitive task for financial institutions. These manual efforts are difficult to scale and can lead to inconsistencies in communication.

Solution: AI voice agents can automate these outbound calls, reminding customers of upcoming payments and providing them with self-service options to make payments or connect with a support agent. This proactive outreach improves collection rates and frees up financial advisors to handle more complex customer needs. This process relies on a secure and compliant communication channel to handle sensitive financial information and build customer trust.

Fraud Detection & Account Alerts

Problem: Financial fraud is a persistent and growing threat, and traditional identity verification methods over the phone can be vulnerable to social engineering. Protecting customer accounts requires a more dynamic and secure approach to authentication.

Solution: AI voice agents can be integrated with voice biometric systems to provide a secure and convenient way to authenticate customers based on their unique voiceprint. They can also proactively send automated alerts for suspicious account activity, allowing for immediate action to secure the account. The effectiveness of this depends on a platform that supports real-time, high-quality audio streaming, which is a crucial component of a multi-layered fraud detection system.

AI Voice Agents in E-Commerce & Retail

For e-commerce and retail businesses, AI voice agents are creating more engaging, efficient, and personalized customer experiences.

Voice-Powered Order Tracking & Returns

Problem: "Where is my order?" is one of the most common customer inquiries, creating a significant and constant call volume for retail support centers. Similarly, managing returns can be a cumbersome process for both the customer and the business.

Solution: AI voice agents can provide customers with instant, real-time updates on their order status and guide them through the return process through a natural, conversational interface. This self-service option is available 24/7, dramatically reducing the burden on human agents and improving customer satisfaction. Integrating this requires APIs that can connect seamlessly with e-commerce platforms and order management systems.

Promotional Campaigns & Feedback Collection

Problem: Conducting outbound promotional campaigns to notify customers of sales or new products and collecting customer feedback over the phone requires a significant investment in time and manpower. Scaling these efforts during peak seasons like holidays is especially challenging.

Solution: AI voice agents can automate these outbound calls, delivering personalized promotional messages and gathering valuable customer feedback at scale. These agents can reach thousands of customers in a short period, making campaigns more efficient and cost-effective. A scalable and reliable platform is ideal for running such large-scale outbound campaigns, with cross-platform SDKs ensuring a consistent experience across all customer devices.

AI Voice Agents for Restaurants

The highly competitive restaurant industry is leveraging AI voice agents to improve operational efficiency in order taking, reservation management, and customer service.

Automated Order Taking and Reservation Management

Problem: During peak hours, restaurant staff are often too busy with in-house guests to answer the phone, leading to missed takeout orders and reservation opportunities. This results in lost revenue and a frustrating experience for customers trying to connect with the restaurant.

Solution: An AI voice agent can handle a high volume of incoming calls simultaneously, taking complex orders and booking reservations directly into the restaurant's system without human intervention. This frees up staff to focus on providing excellent service to in-person customers while ensuring no call goes unanswered. Implementing a natural and intuitive voice-based system requires high-quality audio and low latency to create a seamless and efficient experience.

Handling Modifications, Cancellations, and Delivery Coordination

Problem: Managing last-minute changes to orders, processing cancellations, and coordinating with delivery drivers adds a significant layer of complexity to daily restaurant operations. These real-time communications are critical but can easily overwhelm staff during busy periods.

Solution: AI voice agents can adeptly handle these real-time requests, automatically updating the restaurant's point-of-sale system and communicating with delivery personnel without manual intervention. This ensures that all parties—the customer, the restaurant, and the delivery driver—are always in sync. The real-time nature of a powerful communication platform is essential for the fast-paced restaurant environment, ensuring that all updates are transmitted instantly and reliably.

Customer Feedback and Loyalty Campaigns

Problem: Gathering feedback from diners to improve service and keeping them engaged with loyalty programs can be a difficult and time-consuming task for busy restaurant owners. As a result, many valuable customer insights are lost, and loyalty-building opportunities are missed.

Solution: AI voice agents can be programmed to conduct automated follow-up calls to gather feedback on the dining experience and inform customers about loyalty rewards and special offers. This consistent outreach helps build stronger customer relationships and provides a steady stream of data for service improvement. A scalable platform allows restaurants to easily implement these automated campaigns, helping them to improve their offerings and drive repeat business.

AI Voice Agents in Insurance

The insurance industry is using AI voice agents to streamline claims processing, improve customer engagement, and combat fraud.

Claims Processing and Virtual FNOL (First Notice of Loss)

Problem: The initial reporting of a claim, known as the First Notice of Loss (FNOL), is often a manual and time-consuming process for both the customer and the insurance company. This can lead to delays and inaccuracies at the most critical stage of the claims journey.

Solution: AI voice agents can guide customers through the FNOL process 24/7, conversationally collecting all necessary information and automatically initiating the claim in the system. For more complex claims, the AI agent can seamlessly transition the call to a live video session with a human adjuster. The ability to integrate high-quality video APIs for virtual inspections and real-time assessments can accelerate the entire claims process and improve customer satisfaction.

Policy Renewals and Premium Reminders

Problem: Manually contacting every customer for policy renewals and premium reminders is a significant operational overhead for insurance companies. This repetitive work is not only costly but also prone to human error, potentially leading to missed renewals and lapsed policies.

Solution: AI voice agents can automate outbound renewal and reminder calls, ensuring timely and consistent communication with policyholders. This proactive engagement can significantly improve policy retention rates and ensure on-time payments. The reliability and scalability of a communications platform are ideal for automating these critical customer touchpoints, ensuring that no renewal opportunity is missed.

Fraud Detection and Identity Verification

Problem: Insurance fraud costs the industry billions of dollars annually, and verifying the identity of claimants over the phone can be a weak point in the security chain. Detecting fraudulent claims requires sophisticated tools that can identify subtle red flags.

Solution: AI voice agents can use advanced voice biometrics to securely authenticate policyholders, adding a strong layer of security to the verification process. They can also be trained to analyze speech patterns and flag suspicious conversations for review by a specialized fraud detection team.  Providing a secure and crystal-clear channel for communication is integral to an effective fraud detection and prevention strategy.

Implementing AI Voice Agents with VideoSDK

Understanding the potential of AI voice agents is the first step; building them is the next. A successful implementation requires orchestrating several complex technologies to create a fluid, human-like conversational experience. This is where a dedicated SDK designed for real-time communication becomes invaluable.

Getting Started with an AI Voice Agent SDK

To bring the use cases discussed above to life, developers need a streamlined way to integrate AI capabilities into a communication framework. An AI Voice Agent SDK, such as the one offered by VideoSDK, provides pre-built functionalities that handle the underlying complexities of real-time communication and AI integration. This allows developers to focus on crafting the agent's logic and personality rather than building the foundational infrastructure from scratch. The core of such an SDK revolves around four key components working in perfect harmony.

Overview of Core Components

1. Real-Time Streaming: This is the backbone of any live conversation. The SDK must manage the low-latency, bidirectional streaming of audio data between the user and the AI agent, ensuring the conversation flows naturally without awkward delays or interruptions.
2. Speech-to-Text (STT): To understand the user, the AI agent needs to convert their spoken words into text. The SDK integrates with powerful STT engines that transcribe the user's audio in real-time, providing an accurate textual input for the AI model to process.
3. Text-to-Speech (TTS): Once the AI has formulated a response, it needs to be converted back into natural-sounding speech. The SDK uses advanced TTS engines to generate high-quality, human-like audio, which is then streamed back to the user. The quality of the TTS is critical for user adoption and a positive experience.
4. Agent Orchestration: This is the brain of the operation. The SDK orchestrates the entire workflow, managing the real-time flow of data between the STT service, your business logic or large language model (LLM), and the TTS service. This ensures that the agent can listen, think, and speak in a seamless, uninterrupted loop.

Supported Integrations for Maximum Flexibility

No single AI provider excels at everything. A flexible platform should allow developers to choose the best tools for their specific needs. VideoSDK's AI Voice Agent framework is designed to be plug-and-play, supporting integrations with leading AI services. Developers can mix and match providers for different components, including:

• Speech-to-Text: Integrations with powerful engines like Google STT and OpenAI's Whisper ensure high-accuracy transcriptions across various languages and accents.
• Text-to-Speech: To create lifelike and emotionally resonant voices, the platform supports leading TTS providers like ElevenLabs and services from OpenAI.

This "bring your own AI" model gives developers the freedom to leverage the best-in-class technology and future-proof their applications against a rapidly evolving AI landscape.

SIP/PSTN Integration for Telephony-Grade Quality

While many AI interactions happen within apps, the ability to connect with traditional phone networks is crucial for countless business use cases, from customer service call centers to automated appointment reminders. The integration of Session Initiation Protocol (SIP) and Public Switched Telephone Network (PSTN) gateways is a vital feature. This allows the AI voice agent to make and receive calls from standard phone numbers, extending its reach beyond the digital-only world. VideoSDK's support for SIP/PSTN ensures that businesses can deploy AI agents into their existing telephony workflows, providing a seamless, telephony-grade quality experience for every user, regardless of how they connect.

Key Steps to Build Your Own Voice Agent

Here’s a step-by-step guide to creating your own AI voice agent using VideoSDK:

Step 1: Choose the Voice Model (TTS + STT)

The first step is to select the text-to-speech and speech-to-text models that best suit your application. Consider factors like language support, accuracy, and the desired vocal characteristics of your agent.

Select providers based on:

• Latency requirements (e.g., <300ms for real-time calls)
• Language coverage (multi-lingual support for global deployments)
• Voice customization (brand-aligned tone & gender)

Here is the example of the OpenAI TTS model.

from videosdk.plugins.openai import OpenAITTS
from videosdk.agents import CascadingPipeline

# Initialize the OpenAI TTS model
tts = OpenAITTS(
    # When OPENAI_API_KEY is set in .env - DON'T pass api_key parameter
    api_key="your-openai-api-key",
    model="tts-1",
    voice="alloy",
    speed=1.0,
    response_format="pcm"
)

#  Add tts to cascading pipeline
pipeline = CascadingPipeline(tts=tts)

Alternatively you can try Google Gemini and AWS Nova Sonice

Here is the example of the OpenAI STT model.

from videosdk.plugins.openai import OpenAISTT
from videosdk.agents import CascadingPipeline

# Initialize the OpenAI STT model
stt = OpenAISTT(
    # When OPENAI_API_KEY is set in .env - DON'T pass api_key parameter
    api_key="your-openai-api-key",
    model="whisper-1",
    language="en",
    prompt="Transcribe this audio with proper punctuation and formatting."
)

#  Add stt to cascading pipeline
pipeline = CascadingPipeline(stt=stt)

Step 2: Configure VideoSDK for real-time transport

Next, you'll need to set up your VideoSDK environment to handle the real-time transport of audio data. This involves configuring your authentication tokens and meeting IDs to enable the AI agent to join a communication session. You will need to set up a .env file to securely store your API keys and tokens.

Here is the OpenAI API key to Configure VideoSDK for real-time transport 

VIDEOSDK_AUTH_TOKEN = your_videosdk_auth_token;
OPENAI_API_KEY = your_openai_api_key;

If you are using gemini or aws nova sonic you will need to provide their respective api key

Step 3: Create prompt-based flows

Define the conversational logic of your AI agent by creating prompt-based flows. This involves scripting the agent's initial greetings, questions, and responses based on potential user inputs. You can create a custom agent by inheriting from the base Agent class. 

from videosdk.agents import Agent, AgentSession, WorkerJob, RoomOptions, JobContext
import asyncio

class VoiceAgent(Agent):
    def __init__(self):
        super().__init__(
            instructions="You are a helpful voice assistant that can answer questions and help with tasks."
        )

    async def on_enter(self) -> None:
        """Called when the agent first joins the meeting"""
        await self.session.say("Hi there! How can I help you today?")

    async def on_exit(self) -> None:
        """Called when the agent exits the meeting"""
        await self.session.say("Goodbye!")

Step 4: Add fallback and escalation logic

It's crucial to account for scenarios where the AI agent may not understand a user's request or when an error occurs. Implementing fallback logic to provide a helpful response and, if necessary, a mechanism to escalate the conversation to a human agent is a best practice.

The VideoSDK AI Agent SDK allows you to handle these situations by overriding specific methods in your custom agent class.

Handling Unrecognized Intents (Fallback)

If the Large Language Model (LLM) cannot determine the user's intent or if the user's speech is unclear, you can define a fallback behavior. In this example, if the agent doesn't understand, it will ask the user to rephrase their request.

from videosdk.agents import Agent, AgentSession
from videosdk.llm import LLM
from videosdk.stt import STT
from videosdk.tts import TTS

class VoiceAgent(Agent):
    def __init__(
        self,
        llm: LLM,
        stt: STT,
        tts: TTS,
    ):
        super().__init__(
            llm=llm,
            stt=stt,
            tts=tts,
            instructions="You are a helpful voice assistant that can answer questions and help with tasks."
        )

    async def on_enter(self) -> None:
        """Called when the agent first joins the meeting"""
        await self.session.say("Hi there! How can I help you today?")

    async def on_fallback(self) -> None:
        """Called when the agent cannot understand the user's intent."""
        await self.session.say("I'm sorry, I didn't quite catch that. Could you please rephrase?")

    async def on_exit(self) -> None:
        """Called when the agent exits the meeting"""
        await self.session.say("Goodbye!")

Handling Errors and Escalation

For more critical errors, or if the user explicitly asks to speak to a human, you can implement an escalation path. This could involve triggering a notification, transferring the call, or providing the user with contact information for human support.

The on_error method can be used to catch exceptions that occur during the agent's operation.

import logging

# ... (previous imports)

class VoiceAgent(Agent):
    # ... (__init__ and on_enter methods)

    async def on_fallback(self) -> None:
        """Called when the agent cannot understand the user's intent."""
        await self.session.say("I'm sorry, I didn't quite catch that. Could you please rephrase?")

    async def on_error(self, error: Exception) -> None:
        """Called when an error occurs."""
        logging.error(f"An error occurred: {error}")
        # Simple escalation: inform the user and provide a support email.
        await self.session.say("It seems I've run into a technical issue. Please contact our support team at support@example.com for assistance.")
        # In a more advanced scenario, you could trigger an API call
        # to a human handoff service here.

    async def on_exit(self) -> None:
        """Called when the agent exits the meeting"""
        await self.session.say("Goodbye!")

In a real-world application, the on_error or a custom function tool could be used to initiate a more sophisticated escalation process, such as:

• Human Handoff: Triggering a workflow in a CRM or helpdesk system to alert a human agent to join the call.
• Ticket Creation: Automatically creating a support ticket with the conversation transcript.
• SIP Transfer: If using SIP integration, transferring the call to a pre-defined human agent's phone number.

By implementing these fallback and escalation mechanisms, you ensure that your AI voice agent provides a reliable and helpful experience, even when faced with ambiguity or errors.

Step 5: Deploy to production

Once you have thoroughly tested your AI voice agent, you can deploy it. The VideoSDK CLI allows you to run your agent locally for testing and then deploy it to the VideoSDK Cloud.

# Run the AI Deployment locally
videosdk run

# Deploy the AI Deployment
videosdk deploy

Best Practices for Scale and Accuracy

To ensure your AI voice agent performs optimally and delivers a high-quality user experience as your user base grows, consider these best practices:

Use context-aware agents (via MCP or A2A Protocols)

A truly intelligent agent understands the flow of conversation. Instead of treating each user query as an isolated event, a context-aware agent maintains a memory of the dialogue. This allows for more natural and efficient interactions.

VideoSDK facilitates this through Agent-to-Agent (A2A) communication protocols. For example, a general-purpose AI voice agent could handle initial user queries and then, upon identifying a specialized need (like a technical support issue), can seamlessly forward the query and the conversation history to a specialist agent. This ensures the user doesn't have to repeat themselves, creating a smoother experience.

Cache common responses

Many businesses find that a significant portion of their customer inquiries are repetitive. For these frequently asked questions (e.g., "What are your business hours?" or "How do I reset my password?"), caching the generated audio response can significantly improve performance.

By storing the pre-rendered TTS audio for common answers, you can:

• Reduce Latency: Deliver answers almost instantaneously, as you're bypassing the real-time TTS generation step.
• Lower Costs: Minimize the number of API calls to TTS services, leading to direct cost savings, especially at scale.
• Increase Consistency: Ensure the answer to a common question is always delivered in the same clear and consistent manner.

Personalize with user metadata

Personalization is key to transforming a generic interaction into a memorable customer experience. By leveraging user metadata—such as their name, past purchase history, or support ticket status—your AI voice agent can provide tailored and empathetic responses.

For instance, an e-commerce voice agent could greet a returning customer with:

"Welcome back, [Customer Name]! I see your recent order for the [Product Name] has been shipped. Are you calling about that, or is there something else I can help you with today?"

This level of personalization, achievable by integrating your AI agent with your CRM or user database, makes the interaction feel more human and significantly improves customer satisfaction.

Use multi-turn dialogs via LLM

Early voice bots were often limited to simple, one-off commands. Modern AI voice agents, powered by sophisticated Large Language Models (LLMs), excel at handling multi-turn dialogues. This means the agent can manage complex, evolving conversations where the user's intent might be clarified over several exchanges.

For example, a user might start by saying, "I need a flight to New York." The agent can then ask clarifying questions like, "Which airport in New York?", "What date would you like to travel?", and "Are you looking for a one-way or round-trip ticket?" The LLM's ability to maintain context throughout this back-and-forth is what makes a truly conversational and useful AI possible. VideoSDK’s architecture is designed to support these stateful, long-running conversations seamlessly.

Conclusion

The proliferation of AI voice agents across industries in 2025 is a clear indicator of a fundamental shift in how we interact with technology. From making healthcare more accessible to providing 24/7 customer support, voice is becoming the new frontier of user experience. As these systems grow more sophisticated, they will unlock unprecedented opportunities for businesses to enhance customer engagement, boost operational efficiency, and drive growth.

For developers, marketers, and founders looking to stay ahead of the curve, the time to embrace AI-powered voice solutions is now. With its robust, scalable infrastructure, flexible integrations with top AI providers, and a developer-friendly SDK, VideoSDK provides the ultimate platform to build the next generation of intelligent voice agents. Whether you're developing for iOS, Android, or the web, our comprehensive tools empower you to bring your most ambitious voice agent projects to life.

Imagine a world where your customers can interact with an AI-powered agent that understands their needs, responds instantly, and provides a seamless experience across channels. This is the reality of AI Voice Agents in 2025.

In today’s fast-paced digital landscape, businesses are striving for ways to automate customer service and improve user experience. With AI-powered solutions like voice agents, SaaS companies can offer cutting-edge support that scales effortlessly. These intelligent systems are no longer a futuristic concept but a present-day reality, transforming how businesses engage with their customers.

In this blog, we’ll guide you through building an AI Voice Agent in minutes using VideoSDK’s powerful tools and features, focusing on ease of integration, scalability, and customization. By the end, you'll understand the core components and be ready to deploy a sophisticated voice agent that can handle customer interactions, schedule appointments, and much more.

What Are AI Voice Agents, and Why Build One in 2025?

An AI voice agent is an advanced software program designed to understand and respond to human speech in a natural, conversational manner. Unlike traditional, rigid IVR systems that rely on keypad inputs, AI voice agents leverage technologies like natural language processing to engage in human-like dialogue, automating both inbound and outbound calls without direct human oversight.

While off-the-shelf voice agent solutions exist, building your own provides unparalleled advantages in customization, brand identity, and data control. A custom voice agent allows you to create a unique and consistent auditory presence that aligns with your brand's personality, a critical differentiator in a crowded market. This ensures that every customer interaction, from a simple query to a complex transaction, reinforces your brand identity.

The advantages of integrating a bespoke AI voice agent into your operations are substantial:

• Enhanced Customer Experience: Provide instant, 24/7 support and eliminate frustrating wait times, leading to higher customer satisfaction.
• Increased Operational Efficiency: Automate routine tasks like appointment scheduling and order updates, freeing up human agents to handle more complex issues.
• Cost Reduction: Scale your customer communication capabilities to handle high call volumes without a proportional increase in operational costs.
• Scalability and Consistency: Deliver standardized, high-quality responses that align with your brand's tone, ensuring a consistent experience for every customer.
• Data-Driven Insights: Gain valuable insights from customer interactions to further refine your products and services.

Getting Started with Your AI Voice Agent: The Essential Toolkit

Building a powerful AI voice agent involves the seamless integration of several core technologies. Here’s a breakdown of the essential components and their roles in creating a conversational AI experience.

Automatic Speech Recognition (ASR)

Automatic Speech Recognition (ASR), also known as speech-to-text, is the foundational technology that converts spoken language into written text. It is the "ears" of your AI agent, enabling it to listen to and understand human speech in real-time. 

The accuracy and speed of your ASR system are critical for a smooth conversational flow. A high-quality ASR engine ensures that the user's words are transcribed precisely, which is the first and most crucial step for the agent to comprehend the request. Modern ASR can handle various languages, accents, and even operate in noisy environments, making it a robust solution for global businesses. For any developer looking to build a voice-driven application, integrating a powerful real-time transcription API is non-negotiable.

Natural Language Processing (NLP) & Large Language Models (LLMs)

Natural Language Processing (NLP) is a field of AI that gives machines the ability to understand, interpret, and generate human language. Large Language Models (LLMs) are an advanced application of NLP, trained on massive datasets to understand context, nuance, and intent, enabling them to generate coherent and relevant responses.

NLP and LLMs are the "brain" of your AI voice agent. While ASR transcribes what is said, NLP/LLMs figure out what is meant.  They analyze the transcribed text to identify user intent, extract key information, and formulate a contextually appropriate response. This combination allows for dynamic, human-like conversations that go far beyond scripted, rule-based interactions, leading to more satisfying and effective user engagement.

Text-to-Speech (TTS)

Text-to-Speech (TTS) technology converts written text back into natural-sounding human speech. This is the "voice" of your AI agent, giving it the ability to communicate its responses audibly.

The quality of the TTS voice is paramount for a positive user experience. A robotic, unnatural voice can be off-putting, while a clear, expressive, and human-like voice builds trust and keeps users engaged. Modern TTS systems allow for customization of voice, tone, gender, and accent, enabling you to create a voice personality that perfectly reflects your brand. This consistency across touchpoints strengthens brand recall and fosters a more personal connection with your audience.

Real-Time Communication (WebRTC)

WebRTC (Web Real-Time Communication) is an open-source framework that enables real-time voice, video, and data communication directly between web browsers and devices without requiring plugins.

WebRTC is the "nervous system" that transmits the audio data between the user and the AI agent instantly. It provides the low-latency, secure, and reliable infrastructure necessary for seamless, real-time conversations. Whether you are building for the web, iOS, or Android, leveraging a robust Voice Calling API SDK powered by WebRTC is essential. VideoSDK offers highly reliable, cross-platform SDKs that allow you to deploy AI voice agents and other real-time communication features with just a few lines of code, ensuring a scalable and secure implementation anywhere in the world. By combining these powerful technologies on a flexible platform like VideoSDK, you can build and deploy a sophisticated AI voice agent that not only meets but exceeds customer expectations in 2025.

How to Build an AI Voice Agent in 6 Simple Steps with VideoSDK

Building a state-of-the-art AI voice agent is no longer a monumental task reserved for large corporations. With VideoSDK's open-source AI Agent SDK, you can create and deploy a powerful, conversational AI agent in minutes. Our Python-based framework is designed for flexibility, allowing you to either use integrated real-time pipelines or build custom agents by combining your preferred STT, LLM, and TTS providers.

Here’s a step-by-step guide to bringing your voice agent to life.

Step 1: Set Up Your Development Environment

First, ensure you have the necessary prerequisites in place. Your backend will host the AI agent, while a client application will connect users to the agent in a VideoSDK meeting room.

Prerequisites:

• Python 3.12 or higher.
• A VideoSDK Auth Token. You can generate these from the VideoSDK dashboard.
• API keys for your chosen third-party services (e.g., OpenAI for LLM, Deepgram for STT, ElevenLabs for TTS).

Installation:Create a Python virtual environment and install the VideoSDK Agents package along with any provider plugins you need.

# Create and activate virtual environment
python3.12 -m venv venv
source venv/bin/activate

# Install the core VideoSDK AI Agent package
pip install videosdk-agents

# Example: Install plugins for OpenAI, Google, and AWS
pip install "videosdk-plugins-openai"
pip install "videosdk-plugins-google"
pip install "videosdk-plugins-aws"

Next, create a .env file in your project's root to securely store your API keys and tokens.

VIDEOSDK_AUTH_TOKEN=YOUR_VIDEOSDK_AUTH_TOKEN
OPENAI_API_KEY=YOUR_OPENAI_API_KEY
ELEVENLABS_API_KEY=YOUR_ELEVENLABS_API_KEY

Step 2: Integrating WebRTC for Real-Time Communication

WebRTC is the cornerstone of real-time voice experiences, enabling ultra-low-latency audio streaming directly between your users and the AI agent. While traditional methods like WebSockets can introduce noticeable lag, especially on unstable networks, WebRTC is specifically designed for reliable, real-time voice in any environment.

VideoSDK abstracts the complexities of WebRTC. The AI Agent SDK handles all the underlying communication, allowing your agent to join a meeting room just like any other participant. Your backend simply needs to initiate the session. The client-side application can be built using any of VideoSDK's SDKs, including React, React Native, Android, and iOS.

Here’s how your Python server instructs the agent to join a meeting:

# main.py
from fastapi import FastAPI
from dotenv import load_dotenv
import os
from your_agent_file import VoiceAgent, create_agent_session # Your custom agent logic

load_dotenv()

app = FastAPI()

@app.post("/join-agent")
async def join_agent(request_data: dict):
    meeting_id = request_data.get("meeting_id")
    auth_token = os.getenv("VIDEOSDK_AUTH_TOKEN")

    if not meeting_id or not auth_token:
        return {"error": "Meeting ID and auth token are required."}

    # Create and start the agent session in the background
    session = await create_agent_session(meeting_id, auth_token)
    await session.start()

    return {"message": "Agent is joining the meeting."}

Step 3: Configuring Speech-to-Text and NLP Capabilities

Accurate and fast transcription is non-negotiable for a voice agent to understand users correctly. Similarly, a high-quality, natural-sounding voice is essential for user engagement. VideoSDK’s CascadingPipeline offers a modular approach, giving you complete control to mix and match the best STT and TTS providers for your needs. You can choose from providers like Deepgram, Google, and more.

Here is how you can configure a pipeline using Google for STT and ElevenLabs for TTS:

# agent_logic.py
from videosdk.agents import Agent, AgentSession, CascadingPipeline
from videosdk.plugins.google import GoogleSTT
from videosdk.plugins.elevenlabs import ElevenLabsTTS

# Define your agent's personality and tools
class VoiceAgent(Agent):
    def __init__(self):
        super().__init__(
            instructions="You are a friendly and helpful assistant."
        )

# Configure the pipeline with your chosen STT and TTS providers
async def create_agent_session(meeting_id: str, auth_token: str):
    stt_config = {"model": "long", "language_code": "en-US"}
    stt_provider = GoogleSTT(config=stt_config)

# Configure OpenAI LLM below

llm_provider = OpenAILLM(
   model="gpt-4o",
   # When OPENAI_API_KEY is set in .env - DON'T pass api_key parameter
   api_key="your-openai-api-key",
   temperature=0.7,
   tool_choice="auto",
   max_completion_tokens=1000
)


    tts_config = {"model_id": "eleven_multilingual_v2"}
    tts_provider = ElevenLabsTTS(config=tts_config)
    
    pipeline = CascadingPipeline(
        stt=stt_provider,
        tts=tts_provider,
        llm=llm_provider
    )

    agent = VoiceAgent()
    session = AgentSession(agent=agent, pipeline=pipeline, meeting_id=meeting_id, auth_token=auth_token)
    return session

Step 4: Adding AI for Contextual Conversations

The Large Language Model (LLM) is the brain of your agent. This is where you integrate models like GPT-4 to process the transcribed text and generate intelligent, context-aware responses. VideoSDK’s framework seamlessly connects your chosen LLM into the conversation flow.

Let's complete the pipeline from the previous step by adding OpenAI's GPT-4 as the LLM.

# agent_logic.py (continued from Step 3)
from videosdk.plugins.openai import OpenAILLM

# ... (VoiceAgent class and other imports) ...

# Configure the pipeline with STT, TTS, and now LLM
async def create_agent_session(meeting_id: str, auth_token: str):
    # ... (STT and TTS provider setup) ...

    llm_config = {"model": "gpt-4"}
    llm_provider = OpenAILLM(config=llm_config)
    
    pipeline = CascadingPipeline(
        stt=stt_provider,
        llm=llm_provider,
        tts=tts_provider,
    )

    agent = VoiceAgent()
    session = AgentSession(agent=agent, pipeline=pipeline, meeting_id=meeting_id, auth_token=auth_token)

    # Add a greeting when the agent joins
    @agent.on_enter
    async def on_enter(session):
        await session.say("Hello! I'm your AI assistant. How can I help you today?")

    return session

With this setup, the audio pipeline is complete: VideoSDK captures user audio, Google transcribes it, OpenAI processes the text and generates a response, and ElevenLabs converts that text back into speech for the user to hear.

Step 5: Deploy and Test Your AI Voice Agent

Your AI agent's backend logic, housed in a web server like FastAPI, can be deployed to any modern cloud service.  Popular choices include serverless platforms like Vercel or AWS Lambda for scalability, or containerized applications on services like AWS Fargate or Google Cloud Run.

Create a videosdk.ymal file with following structure :

version: "1.0"
deployment:
  id: your_ai_deployment_id
  entry:
    path: entry_point_for_deployment
env: # Optional to run your agent locally
  path: "./.env"
secrets:
  VIDEOSDK_AUTH_TOKEN: your_auth_token
deploy:
 cloud: true

Deploy voice agent :

1. Run AI Development Locally:

videosdk run

2. Deploy Voice Agent

videosdk deploy

Testing focuses on two key metrics:

• Latency: Measure the time from when a user finishes speaking to when they hear the agent's response. An ideal response time is under one second to feel natural. VideoSDK's infrastructure is optimized for sub-80ms latency, giving you a strong foundation.
• Accuracy: Review call transcripts and agent responses to check for errors in transcription or intent recognition. Use this data to refine your agent's instructions (prompts) and improve its conversational abilities.

Step 6: Optimize for Scale and Performance

As your user base grows, you'll need to ensure your voice agent can handle high traffic without degrading performance.

Best Practices for Optimization:

• Load Balancing: Deploy your backend server across multiple instances and use a load balancer to distribute incoming requests. This prevents any single server from becoming a bottleneck.
• Efficient Prompt Engineering: Optimize your LLM prompts for speed and clarity. Well-structured prompts reduce the computation required by the model, leading to faster response generation.
• Asynchronous Processing: Leverage asynchronous tasks for non-blocking operations. For instance, if your agent needs to fetch data from an external API, do it asynchronously so it can still handle other conversational turns. VideoSDK's Python SDK is built with async support to facilitate this.
• Monitor Performance Metrics: Continuously track metrics like first-call resolution, average response time, and user sentiment. Use these insights to iteratively improve your agent's logic and performance.

Best Practices for an Exceptional AI Voice Agent Experience

Building an agent that can talk is one thing; creating an experience that feels natural and intelligent is another. Here are the core principles to elevate your AI voice agent from functional to exceptional.

Low Latency is Key

In human conversation, the natural pause between turns is often just a few hundred milliseconds. Any delay beyond that feels awkward and breaks the conversational flow, making the AI feel slow or robotic. This is why ultra-low latency is not just a technical metric but a fundamental requirement for a great user experience. VideoSDK is built for this, with a global mesh network optimized for real-time communication and an AI Agent SDK engineered to minimize delays, typically achieving end-to-end latency of under 600ms. This ensures that interactions are snappy, responsive, and feel as natural as talking to a person.

Contextual Memory

A conversation without memory is just a series of disconnected questions and answers. For an agent to be truly helpful, it must remember what was said earlier in the conversation (short-term memory) and even recall information from past interactions (long-term memory). VideoSDK's framework is designed to support this, allowing you to build agents that maintain context. This enables more coherent, personalized, and intelligent dialogues where the agent can reference past details, understand follow-up questions, and provide truly relevant responses.

Handling Interruptions

Natural conversations are not always perfectly linear; people interrupt each other. A great AI voice agent must handle this gracefully. This is achieved through advanced Voice Activity Detection (VAD), which detects when a user starts speaking and signals the agent to stop talking immediately. VideoSDK’s Agent SDK manages this complex process, allowing for fluid turn-taking where users can jump in, change the topic, or ask for clarification without waiting for the agent to finish its sentence. This capability is crucial for making the interaction feel collaborative rather than scripted.

Conclusion

In 2025, building a powerful, conversational AI voice agent is no longer a futuristic vision but an accessible reality. By combining the core technologies of ASR, NLP/LLMs, and TTS with a robust real-time communication backbone like WebRTC, developers can create truly intelligent systems.

As we've seen, VideoSDK provides a comprehensive, open-source framework that abstracts away the complexities of real-time transport and multi-provider integration. With just a few lines of Python, you can deploy a scalable, low-latency agent equipped with contextual memory, function-calling capabilities, and natural interruption handling.

Whether you're looking to revolutionize customer support, automate sales qualification, or create interactive educational experiences, the tools are at your fingertips. The future of human-computer interaction is here, and with VideoSDK, you have everything you need to build it.

If your business is still relying solely on human-led voice interactions in 2025, you are likely leaving significant efficiency gains and customer satisfaction on the table. The era of clunky, command-based IVR systems is over, replaced by intelligent, human-like AI voice agents that can understand context, manage complex conversations, and even close sales.

The global market for voice AI agents is projected to skyrocket, reflecting a massive shift in how businesses operate and interact with their customers. Valued at $2.4 billion in 2024, the market is expected to reach nearly $47.5 billion by 2034, growing at a compound annual growth rate (CAGR) of 34.8%. Companies are increasingly deploying the best AI voice agents to automate tasks, reduce operational costs, and enhance the customer experience. It's predicted that by 2025, AI will power 95% of all customer interactions. 

This blog post will guide you through the 10 best AI voice agents and platforms in 2025. We'll explore their key features, ideal use cases, and how you can leverage them to build next-generation voice experiences. We will also highlight how VideoSDK's robust infrastructure, with its powerful real-time communication (RTC) capabilities, can empower you to create and scale your own AI-powered voice agents with ease. 

What Are AI Voice Agents, and Why Are They Booming in 2025?

An AI voice agent is a sophisticated software program designed to understand, process, and respond to human speech in a conversational manner. Unlike traditional interactive voice response (IVR) systems that rely on rigid, pre-programmed menus, AI voice agents use a combination of technologies, including automatic speech recognition (ASR), natural language processing (NLP), and text-to-speech (TTS) to engage in dynamic, two-way conversations. These agents can be integrated into various channels, such as phone systems, mobile apps, and smart devices, to automate a wide range of tasks, from answering customer queries to scheduling appointments. 

The boom in AI voice agents in 2025 is driven by several key factors. Businesses are under constant pressure to improve efficiency and reduce operational costs. AI voice agents offer a powerful solution by automating repetitive tasks and handling a high volume of inquiries simultaneously, thus freeing up human agents to focus on more complex and high-value interactions. Furthermore, customer expectations have evolved; today's consumers demand instant, 24/7 support, and AI agents can deliver this level of service without the limitations of a human workforce. The rapid advancements in AI technology, particularly in natural language understanding and generative AI, have also made these agents more human-like and capable of handling nuanced conversations, leading to a more positive customer experience.

The data speaks for itself. In 2025, it's anticipated that 80% of customer service organizations will utilize generative AI to boost agent productivity and the overall customer experience. This widespread adoption is a clear indicator of the significant impact AI voice agents are having on the customer service industry. Organizations that have implemented AI solutions have reported substantial benefits, including up to a 30% reduction in customer service operational costs and a significant increase in customer satisfaction. This trend underscores the importance of integrating AI-powered voice solutions to stay competitive in the modern business landscape. 

Top 10 AI Voice Agents and Platforms in 2025

1. VideoSDK
2. Vapi
3. ElevenLabs
4. Deepgram
5. OpenAI
6. Bland
7. Synthflow
8. Retell AI
9. Voiceflow
10. Murf.ai

VideoSDK: Best for Real-Time AI Voice Agent

VideoSDK provides the foundational infrastructure for creating scalable and low-latency AI voice agents. It’s not just a tool but a comprehensive solution for developers looking to integrate intelligent voice experiences into their applications. This platform is engineered for developers who need to build, deploy, and manage sophisticated AI voice agents that operate in real-time, offering a flexible and powerful alternative to off-the-shelf solutions. Unlike rigid voice bot frameworks, VideoSDK gives you the flexibility, modularity, and global performance needed to build AI voice agents for production that think, speak, and act in real-time. With its robust WebRTC-based architecture, VideoSDK is the go-to choice for building custom, high-performance voice AI applications.

Key Features:

Global WebRTC Infrastructure & Low-Latency Guarantee: VideoSDK is built on a geo-distributed WebRTC architecture that intelligently routes media through the nearest server to the end-user. This engineering ensures audio latency remains under 80ms, which is critical for preventing the awkward pauses and interruptions that plague slower systems. For an AI voice agent, this means conversations are fluid and natural, mirroring human interaction.

Truly Modular and Extensible AI Pipelines: Developers have granular control over the voice agent's "brain." You can plug and play different best-in-class services for each part of the process:

Speech-to-Text (STT): Choose from providers like Google Speech, OpenAI, or specialized services like Deepgram for real-time transcription. You can even switch models on the fly based on the caller's language or dialect.

Large Language Model (LLM): Integrate any LLM of your choice, whether it's OpenAI's GPT series, Anthropic's Claude, or a fine-tuned open-source model you host yourself. This flexibility is key to controlling costs and tailoring the agent's personality and knowledge.

Text-to-Speech (TTS): Select from a range of TTS engines like ElevenLabs for hyper-realistic voices or Amazon Polly for a wide variety of languages and accents.

Context-Awareness with Built-in RAG and Memory: An AI agent is only as smart as its access to information. VideoSDK’s platform includes built-in Retrieval-Augmented Generation (RAG) capabilities. This allows the agent to query external knowledge bases—like a product database, company FAQs, or a user's order history—in real time. The integrated memory ensures the agent remembers previous turns in the conversation, so users don't have to repeat themselves. This combination drastically reduces LLM "hallucinations" by grounding responses in factual data.

Full-Stack Platform SDKs: True cross-platform development is a core strength. An AI voice assistant built with VideoSDK can be deployed natively within your application, regardless of the platform. This includes comprehensive SDKs for web (React, Angular, Vue, Javascript), mobile (iOS and Android, with wrappers for React Native and Flutter), and even specialized environments like Unity.

Telephony (PSTN) and SIP Integration: Your AI voice agent isn't limited to apps. VideoSDK allows you to connect your agent to traditional phone networks. You can acquire phone numbers directly and have your agent answer inbound calls (PSTN) or integrate it into existing enterprise phone systems using the SIP protocol.

Robust Audio Processing: To ensure the STT engine receives the cleanest possible audio for maximum accuracy, VideoSDK includes built-in audio processing features like advanced noise suppression and echo cancellation. This is crucial for real-world environments where background noise is common, such as call centers, drive-thrus, or users on mobile devices.

Flexible and Scalable "Agent Cloud": Deployment is designed for developer choice. You can use VideoSDK's managed "Agent Cloud" to get your voice agent running in minutes without worrying about server management and auto-scaling. For enterprises with specific security or infrastructure requirements, the entire agent framework can be self-hosted on your own cloud or on-premise servers.

Enterprise-Grade Security and Compliance: VideoSDK is architected for trust and security, meeting standards like SOC 2 Type II, GDPR, and HIPAA. This makes it a viable solution for industries handling sensitive information, such as healthcare (for patient scheduling) or finance (for customer verification).

Use Cases:

• E-commerce and Retail - Smart Return & Order Management: An AI voice agent handles inbound calls for product returns. It authenticates the customer, uses RAG to pull up their order history from a Shopify or Magento backend, understands the reason for the return, and initiates the Return Merchandise Authorization (RMA) process—all without human intervention.
• Healthcare - HIPAA-Compliant Appointment Scheduling: A patient calls a clinic to book an appointment. The AI agent, operating within HIPAA guidelines, authenticates the patient, checks the doctor's real-time availability via an API call to the clinic's scheduling software, and books the appointment. It can also handle follow-up tasks like sending confirmation texts.
• SaaS - Interactive In-App Onboarding Assistant: A new user logs into a complex software platform. An in-app voice assistant proactively offers help. The user can ask natural language questions like, "How do I add a new team member to my project?" The agent provides a verbal walkthrough while potentially highlighting the relevant UI elements, drawing its answers from the product's documentation via RAG.
• Logistics and Transportation - Automated Dispatch and ETA Updates: A truck driver can call a dispatch number and, through a voice agent, report their current status, log a completed delivery, or request their next assignment. For customers, an AI agent can provide real-time ETA updates by querying the company's logistics database.
• Hospitality - 24/7 Voice-Based Concierge and Booking: A hotel guest can call the front desk at any hour and interact with an AI agent to request a wake-up call, order room service, or ask for information about local attractions. The agent can also handle new room bookings by checking availability and processing payments.
• FinTech - Secure Customer Authentication and Support: A user calls their bank's support line to report a lost card. The AI agent guides them through a secure, multi-factor voice authentication process. Once verified, it can immediately lock the card and initiate the process for sending a replacement, then log the interaction in the CRM.

Pricing: VideoSDK offers a flexible pricing model that caters to different scales of business. You can find more details on their pricing page.

Plan	Free	Pay-As-You-Go	Enterprise
Description	Launch effortlessly, ideal for exploration and integration	Scale seamlessly as you grow with usage-based pricing	Designed for high-volume demands and customized use cases
Included Minutes	10,000 mins/month (conferencing + streaming) 300 mins/month (add-ons)	Billed based on usage	Starts at 1M minutes
Audio Call Pricing	Free (within limits)	$0.0006 / participant-minute	Discounted pricing based on usage
Video Call Pricing	Free (within limits)	$0.003 / participant-minute	Discounted pricing based on usage
Live Streaming Pricing	Free (within limits)	$0.0015 / viewer-minute	Discounted pricing based on usage
Latency	<80ms globally	<80ms globally	<80ms globally
Network	Global mesh network	Global mesh network	Global mesh network
Deployment Options	Shared infra	Shared infra	Dedicated cloud region stack
Support	Discord community	Community & standard support	99.99% uptime SLAs Best-in-town support Dedicated assistance
Credit Card Required	No	Yes	No (via custom contract)

Vapi: Best for Omnichannel Support

Vapi is a developer-centric platform designed for building, deploying, and scaling AI voice agents across various channels. It's particularly strong for teams that need to create a unified voice experience, whether through traditional phone calls, web, or mobile applications. Vapi acts as an orchestration layer, allowing developers to plug in their preferred models for STT, LLM, and TTS to construct a custom voice AI stack.

Key Features:

• Omnichannel Deployment: Build a single voice agent and deploy it across telephony (PSTN), web (WebRTC), and mobile apps.
• BYO Model Integration: Offers the flexibility to "bring your own" models from providers like OpenAI, Deepgram, and ElevenLabs, enabling performance and cost optimization.
• Developer-Focused: Provides a rich developer ecosystem with detailed documentation, API keys for easy integration, and an active Discord community for support.
• Low-Latency Architecture: Engineered for real-time, responsive conversations, crucial for maintaining user engagement.
• Scalability: Built to handle high volumes of concurrent calls, making it suitable for businesses of all sizes.

Use Cases:

• Automating inbound and outbound customer support calls.
• AI-driven e-commerce order management, package tracking, and dispatch.
• Building lead generation and qualification bots for sales teams.
• Healthcare applications such as automated appointment scheduling.

Pricing:Vapi's pricing is usage-based and modular. The core orchestration costs $0.05 per minute, but the total cost increases as you add third-party services for telephony, LLM, STT, and TTS. A free trial is available with $10 in credits to get started.

ElevenLabs: Best for Expressive AI Voices Agent

ElevenLabs is a leader in voice AI technology, renowned for its ability to generate incredibly realistic, expressive, and human-like speech. While primarily a Text-to-Speech (TTS) provider, its high-quality voice generation is a critical component for creating believable AI voice agents. Developers use the ElevenLabs API to give their agents a distinctive and emotionally resonant voice that can significantly enhance the user experience.

Key Features:

• High-Fidelity Speech Synthesis: Produces natural-sounding audio with lifelike intonation and emotional range.
• Voice Cloning: Allows you to create a digital replica of a specific voice from a short audio sample, perfect for brand consistency.
• Multilingual Support: Supports speech generation in over 29 languages and more than 120 voices.
• Voice Design: Provides tools to create and customize unique synthetic voices by adjusting parameters like age, gender, and accent.
• API for Integration: Offers a robust API that allows developers to easily integrate its TTS capabilities into any AI voice agent platform.

Use Cases:

• Powering AI agents for audiobooks and podcasts with unique character voices.
• Creating voiceovers for videos, e-learning modules, and corporate training.
• Developing AI-powered game characters with dynamic and realistic dialogue.
• Building brand-specific voice assistants for marketing and customer engagement.

Pricing:ElevenLabs offers a tiered subscription model. There is a free plan with a 10,000-character monthly limit. Paid plans start at $5/month for the Starter tier, $11/month for the Creator tier, and go up to $99/month for the Pro plan, with increasing character limits and feature access at each level.

Deepgram: Best for Highly Accurate Speech Recognition

Deepgram is an AI speech platform that provides developers with building blocks for voice applications, centered around its industry-leading Speech-to-Text (STT) models. Its high accuracy and low latency in transcription are vital for any AI voice agent, as understanding the user correctly is the first step to a successful interaction. With the recent addition of Aura, its own TTS model, Deepgram now offers a more complete voice AI platform.

Key Features:

• High-Accuracy STT: Renowned for its fast and precise speech-to-text transcription across more than 30 languages.
• Aura TTS Engine: A text-to-speech model built for responsive, conversational AI that minimizes latency.
• Audio Intelligence: Provides APIs for extracting insights from audio, such as summarization, sentiment analysis, and topic detection.
• Real-Time Processing: Engineered for sub-300ms response times, making it ideal for live, conversational applications.
• Custom Models: Allows businesses to train speech models on their specific audio data to improve accuracy for unique vocabularies or accents.

Use Cases:

• Powering conversational AI and virtual assistants where transcription accuracy is critical.
• Transcribing and analyzing calls in contact centers for quality assurance and compliance.
• Creating accurate transcriptions for media such as podcasts and videos.
• Building voice-controlled applications and devices.

Pricing:Deepgram uses a pay-as-you-go model. New users receive $200 in free credits. The Aura TTS service starts at $0.015 per 1,000 characters. For higher volume usage, Growth and Enterprise plans are available with discounted rates.

OpenAI: Best Open-Source AI Voice Recognition

While not a singular, pre-built voice agent platform, OpenAI provides the essential AI models that serve as the building blocks for creating powerful voice agents. Developers can combine OpenAI's Whisper model for speech recognition, a GPT model (like GPT-4) for intelligence and reasoning, and its TTS models for voice output. The "open" nature refers to the accessibility of its APIs, which allow for deep customization and integration.

Key Features:

• Whisper for STT: A highly accurate, open-source speech recognition model that can be self-hosted or accessed via API.
• GPT Models for LLM: Provides the conversational intelligence, allowing agents to understand context, answer questions, and perform tasks.
• TTS API: Offers a range of natural-sounding voices for generating the agent's spoken responses.
• Agents SDK: OpenAI provides an SDK, particularly for TypeScript, to help developers build real-time, context-aware voice agents more easily.
• Function Calling: Allows the LLM to connect to external tools and APIs, enabling the agent to perform real-world actions like booking appointments or processing orders.

Use Cases:

• Building custom, intelligent voice assistants from the ground up for any application.
• Creating specialized agents that can hand off tasks to one another.
• Developing proof-of-concept voice agents for new product ideas.
• Integrating voice control and conversational AI into existing applications.

Pricing:Pricing is based on API usage for each model (Whisper, GPT, TTS). Costs are calculated per token for language models and per second or character for audio models. This modular pricing allows developers to pay only for what they use.

Bland: Best for Generating Custom AI Voices

Bland AI is an API-first platform designed for developers who want to build and scale AI-powered phone agents. It provides the infrastructure to handle high volumes of concurrent calls and is particularly suited for enterprise-level outbound and inbound call automation. While it offers a basic drag-and-drop builder, its core strength lies in its developer-centric tools and integrations.

Key Features:

• High-Volume Calling: Capable of dispatching tens of thousands of calls per hour, making it suitable for large-scale campaigns.
• API-First Architecture: Gives developers deep control over call logic, workflows, and integrations via a flexible API.
• Voice Cloning (Beta): Offers the ability to create custom voices to align with specific brand identities.
• Telephony Integration: Supports integration with major telephony providers like Twilio and Vonage, as well as Bring-Your-Own-Carrier (BYOC) setups.
• Security and Compliance: Meets enterprise security standards, including SOC 2 and HIPAA certifications.

Use Cases:

• Automating high-volume outbound sales and marketing calls.
• Handling large-scale inbound customer service and support inquiries.
• Building AI-powered appointment reminder and confirmation systems.
• Conducting automated surveys and collecting customer feedback.

Pricing:Bland AI has a straightforward usage-based pricing model. Outbound calls are priced at $0.09 per minute and inbound calls at $0.04 per minute. Phone number rental is an additional $15 per month. Be aware that advanced features like voice cloning may incur extra fees.

Synthflow: Best for Building and Deploying AI Voice Agents

Synthflow is a no-code/low-code platform that enables businesses to design, build, and deploy human-like AI voice agents quickly. It is designed to be accessible for both technical and non-technical users, featuring an intuitive drag-and-drop interface. Synthflow bundles together all the necessary components (telephony, STT, LLM, TTS) into a single package, simplifying the development process.

Key Features:

• No-Code Flow Builder: A visual, drag-and-drop interface for designing complex conversational workflows without writing code.
• All-in-One Platform: Includes all necessary components, abstracting away the complexity of integrating multiple APIs.
• Low-Latency Responses: Optimized for fast, sub-400ms response times to ensure natural-sounding conversations.
• Third-Party Integrations: Seamlessly connects with over 200 tools, including CRMs like Salesforce and HubSpot, calendars, and other business systems.
• White-Labeling: Offers an agency plan that allows businesses to rebrand the platform as their own.

Use Cases:

• Automating lead qualification and appointment scheduling for sales teams.
• Providing 24/7 AI-powered customer support and service.
• Building AI receptionists and answering services.
• Creating voice-based surveys and data collection agents.

Pricing:Synthflow offers several tiered plans. The Starter plan is $29/month, the Pro plan is $375/month, and the Growth plan is $750/month, each with included minutes and features. A 14-day free trial is available for the Pro plan. An enterprise plan is also available with volume-based discounts.

Retell AI: Best for Support Teams

Retell AI is a developer-focused platform for building highly responsive, human-like voice agents. Its standout feature is its proprietary conversation engine, which excels at handling conversational nuances like turn-taking and interruptions, making it ideal for dynamic support interactions. Retell AI is designed for production environments where conversational fluidity is paramount.

Key Features:

• Advanced Conversational Engine: Enables agents to handle interruptions and detect end-of-turn with less than 800ms latency, creating a more natural flow.
• Flexible AI Integration: Allows you to use your preferred LLM, including models from GPT and Claude, to power your agent's intelligence.
• Multi-Platform Deployment: Deploy voice agents across web applications, mobile apps, and telephony services like Twilio.
• Comprehensive Monitoring: Provides post-call analysis, sentiment tracking, and task completion data to monitor and improve agent performance.
• Security and Compliance: Supports SOC 2, HIPAA, and GDPR compliance, making it suitable for regulated industries.

Use Cases:

• Building AI-powered customer service agents that can handle complex and unscripted inquiries.
• Creating interactive voice assistants for technical support and troubleshooting.
• Developing AI agents for booking and scheduling that require natural conversation.
• Prototyping and deploying sophisticated voice AI applications.

Pricing:Retell AI uses a pay-as-you-go pricing model with separate charges for each component (voice engine, LLM, telephony). Voice engine costs start at $0.07/minute. There are no platform fees, and users get $10 in free credits to start. Enterprise plans with volume discounts are also available.

Voiceflow: Best for No-Code AI

Voiceflow is a collaborative, no-code platform that allows teams to design, prototype, and deploy conversational AI agents for both voice and chat. It's particularly well-suited for teams with non-technical members, such as designers and product managers, thanks to its intuitive drag-and-drop interface. While strong on chat, its voice capabilities are typically enabled through integrations.

Key Features:

• No-Code Visual Builder: An easy-to-use drag-and-drop canvas for designing complex conversation flows without any programming knowledge.
• Collaborative Workspace: Allows multiple team members to work on agent design in real-time, leaving comments and managing versions.
• Knowledge Base Training: Train your AI agent on your own data by uploading documents, websites, or articles to answer user questions accurately.
• Multi-Channel Deployment: Design an agent once and deploy it across various channels, including websites, mobile apps, and voice assistants like Amazon Alexa.
• LLM Compatibility: Supports various large language models, including GPT-4, Claude, and Gemini, or you can bring your own.

Use Cases:

• Rapidly prototyping and testing new chatbot and voice assistant ideas.
• Building customer support chatbots for websites to handle common queries.
• Creating lead generation bots that capture user information.
• Developing voice applications for smart speakers and other voice-enabled devices.

Pricing:Voiceflow offers a free Sandbox plan for individuals to experiment. The Pro plan starts at $60 per month per editor, and a custom-priced Enterprise plan is available for larger teams needing advanced features and security.

Murf.ai: Best for Generating Studio-Quality AI Voices

Murf.ai is a powerful AI voice generator that specializes in creating studio-quality, realistic voiceovers from text. While not an end-to-end voice agent platform, it excels at providing the high-quality audio output needed to make an agent sound professional and trustworthy. It's an excellent tool for content creators, marketers, and educators who need polished voiceovers for their projects.

Key Features:

• Studio-Quality Voices: Offers a library of over 200 realistic and natural-sounding voices in more than 30 languages.
• Voice Customization: Allows users to fine-tune voice parameters like pitch, tone, and speed to match the desired style and emotion.
• AI Voice Cloning: Provides the ability to create a custom AI voice clone for consistent branding.
• Voice Over Video: An integrated editor that allows you to sync your generated voiceover with videos, images, and background music.
• API Integration: An API is available for developers to integrate Murf's voice generation capabilities into their own applications.

Use Cases:

• Creating professional voiceovers for marketing videos, advertisements, and social media content.
• Producing audio for e-learning courses, training materials, and explainer videos.
• Generating high-quality audio for podcasts and audiobooks.
• Providing the voice for corporate presentations and product demos.

Pricing:Murf.ai has a free plan with limited features. Paid plans include the Creator plan at $19/month and the Business plan at $66/month (billed annually). A custom Enterprise plan is also available for larger teams with unlimited voice generation needs.

Use Case Patterns Emerging in 2025

AI Voice Agents for Agent Assist in Contact Centers

• Pain Point: Human agents in contact centers often waste valuable time searching through extensive knowledge bases or internal documents while on a live call, leading to long silences and increased Average Handle Time (AHT).
• Solution: AI voice agents can act as a real-time co-pilot. The AI listens to the conversation, understands the customer's query, and automatically fetches and displays the most relevant information, policy details, or troubleshooting steps on the agent's screen.
• Example: During an insurance claim call, as the customer describes the incident, the AI agent listens for keywords and instantly surfaces the relevant policy clauses, coverage limits, and required forms, reducing call handling time by up to 40%.

AI Agents for Customer Support and BPOs

• Pain Point: High call volumes for repetitive queries (e.g., order status, password resets) lead to long customer wait times, agent burnout, and high operational costs for Business Process Outsourcing (BPO) centers.
• Solution: Deploy AI voice agents to autonomously handle Tier-1 and Tier-2 support inquiries 24/7. This front line of AI deflects a significant portion of calls, freeing human agents to manage complex escalations and high-value customer interactions.
• Example: A large retail BPO implements AI agents to manage all "Where is my order?" inquiries. The agent authenticates the user, integrates with the logistics backend to provide a real-time status update, and can even initiate a support ticket if the item is lost, resolving 60% of these calls without human intervention.

Voice Agents for Fintech

• Pain Point: Fintech platforms require secure and immediate support for sensitive operations like fraud reporting, transaction verification, and account inquiries, often happening outside standard business hours.
• Solution: Implement AI voice agents with robust security layers, such as voice biometrics, for user authentication. These agents can securely handle routine financial tasks, query transaction histories, and place temporary locks on accounts in real-time.
• Example: A user of a digital wallet notices a suspicious transaction. They call the support line and are greeted by an AI agent that uses the user's voiceprint to verify their identity. The user says, "I don't recognize the last transaction," and the agent immediately flags the charge and freezes the card, preventing further fraud.

Outbound Calling Agents for Reminders and Sales

• Pain Point: Manually calling customers for appointment reminders or sales follow-ups is a monotonous, time-intensive task that doesn't scale and is prone to human inconsistency.
• Solution: Use AI voice agents to automate outbound calling campaigns. The agent can dial thousands of numbers concurrently, deliver personalized messages, and engage in simple two-way conversation to confirm appointments, qualify leads, or process renewals.
• Example: A car dealership uses an AI agent to call customers whose leases are expiring. The agent reminds them of the date, asks if they're interested in renewing or exploring new models, and can directly schedule a test drive with a sales representative based on calendar availability.

Intelligent IVR Replacement for Enterprises

• Pain Point: Traditional Interactive Voice Response (IVR) systems with rigid, numbered menus ("Press 1 for sales, press 2 for support...") are a major source of customer frustration and often fail to resolve issues, leading to misrouted calls.
• Solution: Replace the legacy IVR with a conversational AI "front door." This AI agent understands natural language, allowing callers to state their intent immediately ("I need to find out if you have the new X-model laptop in stock"). It can either resolve the query directly or route the call to the correct department with the full context of the conversation.
• Example: A major airline replaces its IVR. A traveler calls and says, "My flight to San Francisco was just canceled, I need to get on the next one." The AI agent authenticates the caller, finds their booking, and rebooks them on the next available flight, all within a single, seamless conversation.

Proactive Voice Notifications for Critical Events

• Pain Point: Email or SMS alerts for urgent events like service outages, potential fraud, or flight cancellations can be easily missed or ignored by customers.
• Solution: Trigger automated, outbound voice calls for time-sensitive alerts. An AI agent can deliver the critical information clearly and can even ask for a verbal confirmation to ensure the message was received.
• Example: A financial institution's system flags a potentially fraudulent transaction. It immediately triggers an AI-powered call to the customer that says, "We've detected a possible fraudulent charge of $500 on your card. Please say 'yes' if this was you or 'no' if it was not."

Autonomous Scheduling and Reminders

• Pain Point: The back-and-forth communication required to schedule appointments or meetings is a significant administrative burden for both businesses and their clients.
• Solution: Deploy an AI agent that integrates directly with calendar systems (e.g., Google Calendar, Microsoft Outlook). The agent can view real-time availability, offer open slots to the user, book the appointment, and send automated reminders.
• Example: A patient needs to book a follow-up with their doctor. They call the clinic's AI scheduler, which offers available times. The patient chooses a slot, and the agent books it directly in the doctor's calendar and sends an email and SMS confirmation to the patient.

Debt Collection with Empathy + Compliance

• Pain Point: Debt collection is a highly regulated and emotionally charged process. Human agents can struggle with maintaining a consistent, empathetic tone while adhering strictly to compliance rules like the FDCPA.
• Solution: Utilize AI voice agents programmed with an empathetic tone and a script that is hard-coded for compliance. The agent can handle initial outreach, offer predefined payment plans, and process payments securely, ensuring every interaction is professional and legally sound.
• Example: A collections agency uses an AI agent for first-contact calls. The agent clearly states all required legal disclosures, offers a flexible payment plan without judgment, and can process a payment over the phone, all while logging the call for compliance auditing.

Language-Localized Customer Support at Scale

• Pain Point: Offering high-quality, 24/7 customer support in multiple languages is logistically complex and often too expensive for businesses to maintain.
• Solution: Deploy a single, multilingual AI voice agent. The agent can be programmed to detect the caller's language or offer a language choice, then switch its STT, LLM, and TTS models instantly to provide a fully localized support experience.
• Example: A global software company uses one AI agent for its European support line. When a caller from France begins speaking, the agent responds in fluent French. The next call from Germany is handled seamlessly in German, drawing answers from the same central knowledge base.

AI Voice Receptionists for SMBs

• Pain Point: Small and medium-sized businesses (SMBs) often can't afford a full-time human receptionist, which can lead to missed calls, lost business opportunities, and an unprofessional image.
• Solution: Implement an AI voice agent that acts as a virtual receptionist. It can answer calls 24/7, provide answers to frequently asked questions (e.g., business hours, location), intelligently route calls to the right employee's mobile phone, or take detailed messages.
• Example: A boutique marketing agency uses an AI receptionist. The agent answers calls with the agency's name, asks callers about their needs, and can distinguish between a new business lead (which gets routed directly to the founder) and a vendor call (which goes to voicemail).

Voice-Based Surveys and Feedback Collection

• Pain Point: Traditional text and email surveys suffer from notoriously low response rates, and they rarely capture detailed, qualitative insights.
• Solution: Automate customer feedback collection with engaging, post-interaction AI voice calls. The AI agent can ask open-ended questions and capture nuanced, natural language responses, providing richer data than a simple 1-5 rating scale.
• Example: An online retailer programs an AI agent to call customers three days after their product is delivered. The agent asks, "How was your experience?" and can follow up with questions like, "What's one thing we could do to make it better?" The transcribed answers are then analyzed for sentiment and product insights.

LLM-Powered In-App Voice Companions

• Pain Point: Applications in gaming, education, and the metaverse often feel static and lack truly interactive, immersive elements to keep users engaged.
• Solution: Embed an AI voice agent directly into the application as a character, guide, or companion. Powered by a flexible LLM and a real-time communication platform like VideoSDK, this agent can engage in dynamic, context-aware conversations that enhance the user experience.
• Example: A language-learning app features an AI "travel guide" who acts as a conversation partner. The user can practice speaking with the AI character, asking for directions or ordering food in a new language, and the AI responds realistically, corrects pronunciation, and makes the learning process feel like a real-world interaction.

Why VideoSDK  is the best choice among all the available option

While the market offers a range of excellent point solutions—from specialized TTS engines like ElevenLabs to no-code builders like Voiceflow—VideoSDK stands apart as the definitive choice for developers who need to build truly custom, high-performance, and scalable AI voice agents. The key difference lies in its architecture and philosophy. VideoSDK provides the core, real-time infrastructure and a fully modular AI pipeline, giving you complete control over your creation without sacrificing performance.

Unlike platforms that lock you into their specific ecosystem or abstract away critical components, VideoSDK empowers you with a developer-first toolkit. You are not just building on a platform; you are building with a foundational technology. This means you can select the absolute best-in-class models for every part of your agent's "brain"—be it OpenAI for intelligence, Deepgram for transcription, or ElevenLabs for voice—and orchestrate them on VideoSDK’s global, low-latency WebRTC network. This modularity ensures your agent is not only powerful but also future-proof, allowing you to swap components as AI technology evolves. For businesses aiming to create a differentiated, proprietary voice experience that operates in true real-time, VideoSDK is not just an option; it is the strategic foundation for success.

Comparison of AI Voice Agent Platforms in 2025

Conclusion

The landscape of business communication is undergoing its most significant transformation in decades, and AI voice agents are at the heart of this revolution. From automating customer support and sales outreach to providing in-app conversational companions, the applications are as vast as they are impactful. We've explored the top platforms of 2025, each offering unique strengths—whether it's the beautiful voices of ElevenLabs, the powerful intelligence of OpenAI, or the rapid deployment of no-code builders like Synthflow.

This is where VideoSDK excels. By providing the foundational, low-latency WebRTC infrastructure and a completely modular AI pipeline, VideoSDK empowers you to build the exact voice agent you envision, powered by the best models on the market. You are in command of every component, ensuring your application is both powerful today and adaptable for tomorrow.

Ready to build the future of voice communication?

Explore VideoSDK's AI Voice Agent capabilities: Dive into our documentation and see how our infrastructure can power your vision.

Start Building for Free: Sign up for a free VideoSDK account and get started with our robust APIs and SDKs.

Talk to an Expert: Book a demo with our solutions team to discuss how to bring your most ambitious voice projects to life. 

AI-powered telephony solutions are revolutionizing customer service, sales, and communication workflows. This comprehensive guide shows you how to build a sophisticated AI telephony agent using VideoSDK's powerful voice agent capabilities, deployed seamlessly on Cerebrium's cloud platform.

What We're Building

We'll create a complete AI telephony system that can:

• Handle both inbound and outbound voice calls
• Integrate with SIP providers like Twilio
• Leverage Google's Gemini AI for intelligent conversations
• Deploy automatically on Cerebrium's scalable infrastructure
• Provide real-time voice processing with minimal latency

Architecture Overview

Our AI telephony agent combines several powerful technologies:

• VideoSDK Agents: The core voice agent framework
• SIP Integration: For telephony connectivity via Twilio
• Gemini AI: Real-time conversational intelligence
• Cerebrium: Cloud deployment and scaling platform

Prerequisites

Before we start, you'll need accounts and credentials for the following services. Here are the links to get you started:

• VideoSDK Auth Token
• Twilio SIP trunking setup
• Google API key for Gemini
• Cerebrium account, follow docs here

Project Structure

Our project follows a clean, modular structure:

├── cerebrium.toml
├── main.py
├── requirements.txt
└── README.md

Initialize Your Project

Let's begin by setting up our project directory and basic configuration using the Cerebrium Command Line Interface (CLI).

pip install cerebrium
cerebrium login
cerebrium init videosdk-telephony-agent

Configure Cerebrium Deployment

First, let's set up our cerebrium.toml configuration file for optimal deployment:

[cerebrium.deployment]
name = "sip-ai-agent"
python_version = "3.12"
include = ["./*", "main.py", "cerebrium.toml"]
exclude = [".venv"]
disable_auth = true

[cerebrium.hardware]
region = "us-east-1"
provider = "aws"
compute = "CPU"
cpu = 2
memory = 4.0
gpu_count = 0

[cerebrium.runtime.custom]
port = 8000
entrypoint = ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]
healthcheck_endpoint = "/"

[cerebrium.scaling]
min_replicas = 1
max_replicas = 2
cooldown = 30
replica_concurrency = 4
scaling_metric = "concurrency_utilization"
scaling_target = 80

[cerebrium.dependencies.paths]
pip = "requirements.txt"

This configuration ensures:

• Scalability: Auto-scaling between 1-2 replicas based on concurrency, ensuring the app can handle fluctuating call volumes.
• Performance: Optimized CPU and memory allocation for real-time voice processing.
• Dependency Management: It clearly points to our requirements.txt file, keeping our dependencies separate and organized.

Define Project Dependencies

Create a requirements.txt file in your project directory, you can also view or download the complete file directly from the project's official GitHub repository

Build the Core AI Agent

Now, let's create our main application in main.py. Here's the complete implementation:

import asyncio
import os
import logging
from contextlib import asynccontextmanager
from typing import Optional
from dotenv import load_dotenv
from fastapi import FastAPI, Request, Response
import uvicorn
from pyngrok import ngrok
from videosdk.plugins.sip import create_sip_manager
from videosdk.agents import Agent, JobContext, function_tool, RealTimePipeline
from videosdk.plugins.google import GeminiRealtime, GeminiLiveConfig

load_dotenv()

logging.basicConfig(level=os.getenv("LOG_LEVEL", "INFO"))
logger = logging.getLogger(__name__)

def create_agent_pipeline():
    """Function to create the specific pipeline for our agent."""
    model = GeminiRealtime(
        api_key=os.getenv("GOOGLE_API_KEY"),
        model="gemini-2.0-flash-live-001",
        config=GeminiLiveConfig(
            voice="Leda", # type: ignore
            response_modalities=["AUDIO"], # type: ignore
        ),
    )
    return RealTimePipeline(model=model)

class SIPAIAgent(Agent):
    """A AI agent for handling voice calls."""

    def __init__(self, ctx: Optional[JobContext] = None):
        super().__init__(
            instructions=(
             "You are a helpful voice assistant that can answer questions and help with tasks. Be friendly and concise."
             "Talk to the user as if you are a human and not a robot."
             ),
            tools=[self.end_call], # type: ignore
        )
        self.ctx = ctx
        self.greeting_message = "Hello! Thank you for calling. How can I assist you today?"
        logger.info(f"SIPAIAgent created")

    async def on_enter(self) -> None:
        pass

    async def greet_user(self) -> None:
        await self.session.say(self.greeting_message) # type: ignore

    async def on_exit(self) -> None:
        pass

    @function_tool
    async def end_call(self) -> str:
        """End the current call gracefully"""
        await self.session.say("Thank you for calling. Have a great day!") # type: ignore
        await asyncio.sleep(1)
        await self.session.leave() # type: ignore
        return "Call ended gracefully"

sip_manager = create_sip_manager(
    provider=os.getenv("SIP_PROVIDER", "twilio"),
    videosdk_token=os.getenv("VIDEOSDK_AUTH_TOKEN"),
    provider_config={
        # Twilio config
        "account_sid": os.getenv("TWILIO_ACCOUNT_SID"),
        "auth_token": os.getenv("TWILIO_AUTH_TOKEN"),
        "phone_number": os.getenv("TWILIO_PHONE_NUMBER"),
    }
)

@asynccontextmanager
async def lifespan(app: FastAPI):
    """Lifespan manager for FastAPI app startup and shutdown."""
    port = int(os.getenv("PORT", 8000))
    try:
        ngrok.kill()
        ngrok_auth_token = os.getenv("NGROK_AUTHTOKEN")
        if ngrok_auth_token:
            ngrok.set_auth_token(ngrok_auth_token)
        tunnel = ngrok.connect(str(port), "http")
        sip_manager.set_base_url(tunnel.public_url) # type: ignore
        logger.info(f"Ngrok tunnel created: {tunnel.public_url}")
    except Exception as e:
        logger.error(f"Failed to start ngrok tunnel: {e}")
    yield
    try:
        ngrok.kill()
        logger.info("Ngrok tunnel closed")
    except Exception as e:
        logger.error(f"Error closing ngrok tunnel: {e}")

app = FastAPI(title="SIP AI Agent", lifespan=lifespan)

@app.post("/call/make")
async def make_call(to_number: str):
    if not sip_manager.base_url:
        return {"status": "error", "message": "Service not ready (no base URL)."}
    agent_config = {"room_name": "Call", "enable_pubsub": True}
    details = await sip_manager.make_call(
        to_number=to_number,
        agent_class=SIPAIAgent,
        pipeline=create_agent_pipeline,
        agent_config=agent_config
    )
    return {"status": "success", "details": details}

@app.post("/sip/answer/{room_id}")
async def answer_webhook(room_id: str):
    logger.info(f"Answering call for room: {room_id}")
    body, status_code, headers = sip_manager.get_sip_response_for_room(room_id)
    return Response(content=body, status_code=status_code, media_type=headers.get("Content-Type"))

@app.post("/webhook/incoming")
async def incoming_webhook(request: Request):
    try:
        content_type = request.headers.get("Content-Type", "")
        if "x-www-form-urlencoded" in content_type:
            webhook_data = dict(await request.form())
        else:
            webhook_data = await request.json()
        logger.info(f"Received incoming webhook: {webhook_data}")

        agent_config = {"room_name": "Incoming Call", "enable_pubsub": True}
        body, status_code, headers = await sip_manager.handle_incoming_call(
            webhook_data=webhook_data,
            agent_class=SIPAIAgent,
            pipeline=create_agent_pipeline,
            agent_config=agent_config
        )
        return Response(content=body, status_code=status_code, media_type=headers.get("Content-Type"))
    except Exception as e:
        logger.error(f"Error in incoming webhook: {e}", exc_info=True)
        return Response(content="Error processing request", status_code=500)

@app.get("/sessions")
async def get_sessions():
    return {"sessions": sip_manager.get_active_sessions()}

@app.get("/")
async def root():
    return {"message": "SIP AI Agent"}

if __name__ == "__main__":
    port = int(os.getenv("PORT", 8000))
    logger.info(f"Starting SIP AI Agent on port {port}")
    uvicorn.run(app, host="0.0.0.0", port=port)

Key Components Explained

1. Agent Pipeline Creation

The create_agent_pipeline() function sets up our Gemini AI model with specific configurations:

• Model: gemini-2.0-flash-live-001 for real-time processing
• Voice: "Leda" for natural-sounding responses
• Modalities: Audio-only responses for telephony

2. SIPAIAgent Class

Our custom agent class inherits from VideoSDK's Agent base class and includes:

• Instructions: Clear behavioral guidelines for the AI
• Tools: Built-in function tools like end_call()
• Lifecycle methods: on_enter(), greet_user(), on_exit()

3. SIP Manager Integration

The SIP manager handles all telephony operations:

• Provider Configuration: Twilio credentials and settings
• Call Management: Both inbound and outbound call handling
• Session Tracking: Active session monitoring

API Endpoints

Our API provides several key endpoints:

• POST /call/make: Initiate outbound calls
• POST /webhook/incoming: Handle incoming call webhooks
• POST /sip/answer/{room_id}: Process SIP responses
• GET /sessions:Monitor active sessions

Environment Configuration

Set up these environment variables for your deployment by adding them to a .env file

# VideoSDK Configuration
VIDEOSDK_AUTH_TOKEN=your_videosdk_token

# AI Configuration
GOOGLE_API_KEY=your_google_api_key

# Twilio Configuration
TWILIO_ACCOUNT_SID=your_account_sid
TWILIO_AUTH_TOKEN=your_auth_token
TWILIO_PHONE_NUMBER=your_phone_number

# Optional
NGROK_AUTHTOKEN=your_ngrok_token
SIP_PROVIDER=twilio

To make these available to your deployment, add them to the Secrets view on your Cerebrium dashboard.

Deploying on Cerebrium

Cerebrium makes deployment incredibly straightforward:

1. Install Cerebrium CLI:

pip install cerebrium

1. Deploy your application:

cerebrium deploy

After the deployment finishes, you will receive a public URL to interact with your application. It will have a format similar to this:

<https://api.aws.us-east-1.cerebrium.ai/v4/p-xxxxxxxx/sip-ai-agent/>

VideoSDK Documentation Resources

For deeper integration and customization, explore these VideoSDK resources:

• AI Agents Introduction
• Quick Start Guide
• Core Components Overview
• Agent Implementation
• Real-time Pipeline
• SIP Integration
• Multiple Agents

Conclusion

Building an AI telephony agent with VideoSDK and deploying on Cerebrium creates a powerful, scalable communication solution. This architecture provides:

• Rapid Development: Get started in minutes with pre-built components
• Enterprise Scale: Handle thousands of concurrent calls
• Cost Efficiency: Pay-per-use pricing model
• Global Reach: Deploy worldwide with minimal latency

The combination of VideoSDK's robust voice agent framework and Cerebrium's intelligent cloud platform creates an ideal environment for modern AI-powered telephony solutions.

Ready to get started? Check out the VideoSDK AI Agents documentation and deploy your first agent on Cerebrium today!

Creating a native-like call experience on iOS using Flutter can be challenging—but with the right tools, it becomes seamless. In this guide, we’ll show you how to build a video calling feature for iOS that feels just like a regular phone call.

Using the flutter_callkit_incoming package, you’ll be able to trigger native iOS call screens, manage VoIP-style incoming call notifications, and handle user interactions like answering or rejecting a call—all without writing any Swift code

Explore the full source code to see how everything fits together.

Introduction to Flutter CallKit Incoming

The flutter_callkit_incoming package simplifies the integration of iOS CallKit into Flutter applications. This package allows developers to:

• Present native iOS call screens.
• Manage incoming call notifications.
• Enhance the overall call experience.

It abstracts the complexities of implementing CallKit in Swift, enabling quick and efficient call handling for iOS users.

Overview of the Application in IOS

Initiating a Call:

• The caller (e.g., Pavan) enters the recipient's unique ID (e.g., Jay) and presses the call button.
• This action triggers a server request to initiate the call, which sends a Firebase Cloud Messaging (FCM) notification to the recipient's device through API, and a fake call is being triggered on the Receiver Caller Side.

Receiving the Call:

• If the app is in the foreground: If the App is in the foreground no need to handle the notification, Firebase Messaging Package looks into it. Firebase Messaging Package provided by Firebase in Flutter helps one to manage the Foreground. 
• If the app is in the background: When it comes to background Firebase provides you the feature using Firebase_background_handler on a method called onBackgroundMessage. Using that we can achieve the concept of handling the background message(Basically the message which is received when the app is closed/Minimised).

Handling Call Status:

• Upon answering or rejecting the call, the recipient's action triggers a server request (update call). This request updates the call status and is communicated back to the caller (Pavan) to reflect the recipient's response.

This structured interaction between client, server, and platform-specific components ensures a smooth and intuitive experience for both the caller and the recipient, providing reliable video communication across devices.

Core Components of the App

The app integrates several core components to manage video calling and notifications seamlessly across iOS platforms:

flutter_callkit_incoming

• Purpose: Provides a native call interface on iOS.
• Function: Displays the incoming call UI and handles actions like answering or rejecting calls, leveraging iOS’s native CallKit functionality without requiring native Swift code.

Push Notifications

• Purpose: Notifies the recipient about incoming calls.
• Function: Uses Firebase Cloud Messaging (FCM) and Apple Push Notification Service (APNs) for iOS to send VoIP notifications, triggering the appropriate call UI even if the app is in the background or inactive.

Firebase Realtime Database

• Purpose: Stores user tokens and caller IDs.
• Function: Ensures secure and real-time communication between users, facilitating the initiation of calls and status updates.

VideoSDK

• Purpose: Powers the video calling functionality.
• Function: Enables real-time video and audio communication, providing high-quality video conferencing features for both Android and iOS users.

Node.js Server

• Purpose: Acts as the backend service for call initiation and status updates.
• Function: Sends push notifications via Firebase and APNs, and updates call statuses (e.g., accepted, rejected) between users.

These core components work together to ensure a smooth, feature-rich experience for both video calling and real-time notifications across devices and platforms.

Prerequisites

Before starting with the development of the video calling app, ensure that the following prerequisites are met:

1. Flutter Development Environment:
   • Install Flutter SDK and set up your development environment. Follow the official Flutter installation guide.
2. Firebase Project:
   • Create a Firebase project in the Firebase Console.
   • Set up Firebase Cloud Messaging (FCM) for push notifications.
3. VideoSDK Account:
   • Sign up for a VideoSDK account at VideoSDK and obtain the required credentials (API keys and authentication tokens).
4. Node.js Server:
   • Set up a Node.js server to manage API requests, handle call initiation, and send push notifications. This server will also interact with Firebase to send call-trigger notifications.

With these prerequisites in place, you'll be ready to begin implementing the video calling functionality, leveraging both Firebase and VideoSDK for a seamless cross-platform experience.

Connecting Firebase to Flutter Using FlutterFire CLI

To easily set up Firebase with your Flutter app, follow these steps:

Step 1: Create a Firebase Project

1. Go to the Firebase Console.
2. Create a new project by following the prompts.

Step 2: Select the Flutter Option

• Once your project is created, navigate to the "Add app" section.
• Choose the Flutter option to proceed.

Step 3: Install Firebase CLI

• Use npm to globally install the Firebase CLI. Run the following command in your terminal:

npm install -g firebase-tools

Step 4: Login to Firebase

• Log in to your Firebase account using the Firebase CLI by running:

firebase login

• This will open a browser window prompting you to sign in with your Google account.

Step 5: Configure Firebase in Flutter Using FlutterFire CLI

• Use the FlutterFire CLI to connect your Flutter project to Firebase
• Select an existing Firebase project or create a new one.
• Choose the platforms (e.g., Android, iOS) you want to integrate Firebase with.
• This will add new dart file named as firebase_option.dart in your project .

Step 6: Add dependency in pubspec.yaml file

• add firebase_core dependency in your pubspec.yaml file to resolve errors

iOS Setup: Enabling PushKit and CallKit

To enable PushKit notifications in your application, it is essential to acquire the necessary certificates from your Apple Developer Program account and set them up for your iOS VoIP application. Follow the steps below:

Step 1: Request a Certificate Using Keychain

1. Open the Keychain Access application on your Mac.

2. Select Certificate Assistant -> Request a Certificate From a Certificate Authority.

3. Enter your email and common name, then click Continue.

4. Modify the certificate’s name and save it.

Step 2: Create an App ID in the Apple Developer Account

This process requires an active Apple Developer Program account. Follow these steps:

1. Log into your Apple Developer account.

2. Navigate to Certificates, Identifiers & Profiles and select Identifiers.

3. Click the + icon to add a new identifier.

4. Add a description, specify your bundle ID, check PushKit under Capabilities, and click Continue.

The image below shows the finished App ID.

Step 3: Create a New VoIP Services Certificate

1. Go to the Certificates section in your Apple Developer Program account.

2. Click to add a new certificate.

3. Select the VoIP Services Certificate and choose the App ID you created.

4. Use the private certificate generated in Keychain Access and click Continue.

5. Download the voip_services.cer file provided by your VoIP service provider.

Step 4: Convert .cer to .p12

1. Double-click the voip_services.cer file to open it in Keychain Access.
2. Locate the certificate titled "VoIP Services: YourProductName".
3. Right-click on it and select Export to save it as a .p12 file.
4. Create a strong password when prompted and save the file securely.

Step 5: Convert .p12 to .pem

1. Open a terminal and navigate to the directory where the .p12 file is saved.
2. Enter the password created earlier.
3. A new file named Certificates.pem will be created in the same directory.

Run the following command:

openssl pkcs12 -in YourFileName.p12 -out Certificates.pem -nodes -clcerts -legacy

Note: The bundle ID of your VoIP services will influence the exact certificate name. This .pem file is now ready for use in your push notification implementation.

PushKit Setup

PushKit will allow us to send notifications to the iOS device. To implement push notifications, you must upload an APN Auth Key. The following details about the app are needed when sending push notifications via an APN Auth Key:

• Auth Key file
• Team ID
• Key ID
• Your app’s bundle ID

Creating an APN Auth Key

1. Visit the Apple Developer Member Center

2. Click on Certificates, Identifiers & Profiles. Go to Keys from the left side. Create a new Auth Key by clicking on the plus button on the top right side.

3. On the following page, add a Key Name, and select APNs.

4. Click on the Register button.

5. You can download your auth key file from this page and upload this file to the Firebase dashboard without changing its name.

6. In your Firebase project, go to Settings and select the Cloud Messaging tab. Scroll down the iOS app configuration and click Upload under APNs Authentication Key

7. Enter Key ID and Team ID. Key ID is in the file name AuthKey\_{Key ID}.p8 and is 10 characters. Your Team ID is in the Apple Member Center under the membership tab or displayed always under your account name in the top right corner.

8 . Enable Push Notifications in Capabilities

9. Enable selected permission in Background Modes

Project Structure

Client
│
├── ios
│   └── Runner
│       ├── AppDelegate.swift
│       ├── Info.plist
│       └── GoogleService-Info.plist
│
├── lib
│   |
│   ├── meeting
│   |   ├── api_call.dart
│   |   ├── join_screen.dart
│   |   ├── meeting_controls.dart
│   |   ├── meeting_screen.dart
│   |   └── participant_tile.dart
│   |
│   ├── firebase_options.dart
│   ├── home.dart
│   └── main.dart
│
├── .env
├── pubspec.yaml
└── README.md

Now go to the server side and setup our server

Step 1 : Create a New Project Directory

mkdir server
cd server 
npm init -y 

Step 2 : Install required dependencies

npm install express cors morgan firebase-admin uuid

Step 3 : Set Up Firebase 

Enable Realtime Database and set the rule true and Firebase Cloud messaging (FCM).

Step 4 :

Download the private key by navigating to Project Settings > Service Accounts, selecting Node.js, and then clicking Download.

Step 5 :

Place this File into your server side and your server side structure look like this.

Server
  ├── node_modules/
  ├── server.js
  ├── callkit-3ec73-firebase-adminsdk-ghfto-9d9fc7a362.json
  ├── package-lock.json
  └── package.json

Step 6 : now go to server.js we have to add several API in our server.js

1. GET /: Returns a "Hello Coding" message to confirm the server is running.
2. POST /register-device: Registers a device by storing its unique ID and FCM token in Firebase.
3. POST /api/add: Stores call details (callerId, roomId, and calleeId) in memory.
4. GET /api/getByCallee/:calleeId: Retrieves call details for a given callee ID from memory.
5. POST /send-call-status: Sends a notification to the caller about the status of a call (e.g., accepted, rejected, ended).
6. POST /send-notification: Sends a notification to a caller with details about an incoming call, including room ID and VideoSDK token.

Step 7 : Now we add below code to run the server at your ip 

const PORT = process.env.PORT || 9000; 
const LOCAL_IP = '10.0.0.161'; // Replace with your actual local IP address 
app.listen(PORT, LOCAL_IP, () => {
console.log(Server running on http://${LOCAL_IP}:${PORT});
 }); 

Step 8 :

we setup ngrok and using this below command we redirect our local ip to temporary public URL that can you share outside to your local network ngrok http http://10.0.0.161:9000

It looks like that we can use this https://8190-115-246-20-252.ngrok-free.app as our server url.

Refer the complete code of server,js here.

VideoSDK is a cutting-edge platform that enables seamless audio and video calling with low latency and robust performance. Start by signing up at VideoSDK, generate your API token from the dashboard, and integrate real-time calling into your app effortlessly!

Now add this token into your .env file

Now add all permission for iOS

For iOS we have to add all the permission in info.plist file

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>CADisableMinimumFrameDurationOnPhone</key>
	<true/>
	<key>CFBundleDevelopmentRegion</key>
	<string>$(DEVELOPMENT_LANGUAGE)</string>
	<key>CFBundleExecutable</key>
	<string>$(EXECUTABLE_NAME)</string>
	<key>CFBundleIdentifier</key>
	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
	<key>CFBundleInfoDictionaryVersion</key>
	<string>6.0</string>
	<key>CFBundleName</key>
	<string>Flutter VideoSDK App</string>
	<key>CFBundlePackageType</key>
	<string>APPL</string>
	<key>CFBundleShortVersionString</key>
	<string>$(FLUTTER_BUILD_NAME)</string>
	<key>CFBundleSignature</key>
	<string>????</string>
	<key>CFBundleVersion</key>
	<string>$(FLUTTER_BUILD_NUMBER)</string>
	<key>LSRequiresIPhoneOS</key>
	<true/>
	<key>NSCameraUsageDescription</key>
	<string>$(PRODUCT_NAME) Camera Usage!</string>
	<key>NSMicrophoneUsageDescription</key>
	<string>$(PRODUCT_NAME) Microphone Usage!</string>
	<key>RTCAppGroupIdentifier</key>
	<string>group.com.example.broadcastScreen</string>
	<key>RTCScreenSharingExtension</key>
	<string>live.videosdk.flutter.example.FlutterBroadcast</string>
	<key>UIApplicationSupportsIndirectInputEvents</key>
	<true/>
	<key>UIBackgroundModes</key>
	<array>
		<string>voip</string>
		<string>fetch</string>
		<string>processing</string>
		<string>remote-notification</string>
	</array>
	<key>BGTaskSchedulerPermittedIdentifiers</key>
	<array>
		<string>dev.flutter.background.refresh</string>
	</array>
	<key>UILaunchStoryboardName</key>
	<string>LaunchScreen</string>
	<key>UIMainStoryboardFile</key>
	<string>Main</string>
	<key>UISupportedInterfaceOrientations</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
		<string>UIInterfaceOrientationLandscapeLeft</string>
		<string>UIInterfaceOrientationLandscapeRight</string>
	</array>
	<key>UISupportedInterfaceOrientations~ipad</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
		<string>UIInterfaceOrientationPortraitUpsideDown</string>
		<string>UIInterfaceOrientationLandscapeLeft</string>
		<string>UIInterfaceOrientationLandscapeRight</string>
	</array>
	<key>UIViewControllerBasedStatusBarAppearance</key>
	<false/>
	
</dict>
</plist>

Along with info.plist file also check the AppDelegate.swift file

import UIKit
import Flutter

@main
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
      application.registerForRemoteNotifications()
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

Okay, let's move forward with integrating the VideoSDK into our project. Please refer to the Quickstart documentation provided in the link and follow the initial steps to build the necessary steps till step 4 which is creating a paticipant_tile.dart screen.

Now, after adding the other files to the Meeting folder, lets create a meeting_screen.dart file through which our meeting will be created, rendered and managed.

import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:videosdk/videosdk.dart';
import 'package:videosdk_flutter_example/home.dart';

import 'package:videosdk_flutter_example/meeting/meeting_controls.dart';
import './participant_tile.dart';
import 'package:http/http.dart' as http;

class MeetingScreen extends StatefulWidget {
  final String meetingId;
  final String token;
  final String url;
  final String callerId;
  String? source;
  MeetingScreen(
      {Key? key,
      required this.meetingId,
      required this.token,
      required this.callerId,
      required this.url,
      this.source})
      : super(key: key);

  @override
  State<MeetingScreen> createState() => _MeetingScreenState();
}

class _MeetingScreenState extends State<MeetingScreen> {
  late Room _room;
  var micEnabled = true;
  var camEnabled = true;

  Map<String, Participant> participants = {};

  @override
  void initState() {
    // create room
    if (widget.source == "true") {
      sendnotification(
          widget.url, widget.callerId, "Call Accepted", widget.meetingId);
    }
    _room = VideoSDK.createRoom(
        roomId: widget.meetingId,
        token: widget.token,
        displayName: "John Doe",
        micEnabled: micEnabled,
        camEnabled: camEnabled,
        defaultCameraIndex: kIsWeb
            ? 0
            : 1 // Index of MediaDevices will be used to set default camera
        );

    setMeetingEventListener();

    // Join room
    _room.join();

    super.initState();
  }

  Future<void> sendnotification(String api, callerId, status, roomId) async {
    await sendCallStatus(
        serverUrl: api, callerId: callerId, status: status, roomId: roomId);
  }

  @override
  void setState(fn) {
    if (mounted) {
      super.setState(fn);
    }
  }

  // listening to meeting events
  void setMeetingEventListener() {
    _room.on(Events.roomJoined, () {
      setState(() {
        participants.putIfAbsent(
            _room.localParticipant.id, () => _room.localParticipant);
      });
    });

    _room.on(
      Events.participantJoined,
      (Participant participant) {
        setState(
          () => participants.putIfAbsent(participant.id, () => participant),
        );
      },
    );

    _room.on(Events.participantLeft, (String participantId) {
      if (participants.containsKey(participantId)) {
        setState(
          () => participants.remove(participantId),
        );
      }
    });

    _room.on(Events.roomLeft, () {
      participants.clear();
      Navigator.pushAndRemoveUntil(
        context,
        MaterialPageRoute(
            builder: (context) => Home(
                  callerID: widget.callerId,
                )),
        (route) => false, // Removes all previous routes
      );
    });
  }

  // onbackButton pressed leave the room
  Future<bool> _onWillPop() async {
    _room.leave();
    return true;
  }

  Future<void> sendCallStatus({
    required String serverUrl,
    required String callerId,
    required String status,
    required String roomId,
  }) async {
    final url = Uri.parse('$serverUrl/send-call-status');
   
    try {
      // Request payload
      final body = jsonEncode({
        'callerId': callerId,
        'status': status,
        'roomId': roomId,
      });

      // Sending the POST request
      final response = await http.post(
        url,
        headers: {
          'Content-Type': 'application/json',
        },
        body: body,
      );

      // Handling the response
      if (response.statusCode == 200) {
        print("Notification sent successfully: ${response.body}");
      } else {
        print("Failed to send notification: ${response.statusCode}");
  
      }
    } catch (e) {
      print("Error sending call status: $e");
    }
  }

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    // ignore: deprecated_member_use
    return WillPopScope(
      onWillPop: () => _onWillPop(),
      child: Scaffold(
        appBar: AppBar(
          title: const Text('VideoSDK QuickStart'),
        ),
        body: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Column(
            children: [
              Text(widget.meetingId),
              //render all participant
              Expanded(
                child: Padding(
                  padding: const EdgeInsets.all(8.0),
                  child: GridView.builder(
                    gridDelegate:
                        const SliverGridDelegateWithFixedCrossAxisCount(
                      crossAxisCount: 2,
                      crossAxisSpacing: 10,
                      mainAxisSpacing: 10,
                      mainAxisExtent: 300,
                    ),
                    itemBuilder: (context, index) {
                      return ParticipantTile(
                          key: Key(participants.values.elementAt(index).id),
                          participant: participants.values.elementAt(index));
                    },
                    itemCount: participants.length,
                  ),
                ),
              ),
              MeetingControls(
                micEnabled: micEnabled,
                camEnabled: camEnabled,
                onToggleMicButtonPressed: () {
                  setState(() {
                    micEnabled = !micEnabled;
                  });
                  micEnabled ? _room.unmuteMic() : _room.muteMic();
                },
                onToggleCameraButtonPressed: () {
                  setState(() {
                    camEnabled = !camEnabled;
                  });
                  camEnabled ? _room.enableCam() : _room.disableCam();
                },
                onLeaveButtonPressed: () {
                  _room.leave();
                },
              ),
            ],
          ),
        ),
      ),
      //home: JoinScreen(),
    );
  }
}

Great, we have successfully added our videosdk meeting screens. Lets deep dive into main.dart file and home.dart file.

main.dart

import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter/material.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import 'package:videosdk_flutter_example/home.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await dotenv.load(fileName: ".env");
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Home(),
    );
  }
}

After creating the main.dart file, now its time to create a home.dart file. In home.dart file we will be working on managing the notification and also the call triggering logic is present in this file.

Future<void> sendNotification({
    required String callerId,
    required String callerInfo,
    required String roomId,
    required String token,
  }) async {
    // Prepare the request payload

    final Map<String, dynamic> payload = {
      'callerId': callerId,
      'callerInfo': {'id': callerInfo},
      'videoSDKInfo': {'roomId': roomId, 'token': token},
    };

    try {
      // Send POST request to the API
      final response = await http.post(
        Uri.parse("${apiUrl!}/send-notification"),
        headers: {'Content-Type': 'application/json'},
        body: jsonEncode(payload),
      );

      // Handle the response from the API
      if (response.statusCode == 200) {
        print('Notification sent successfully');
        if (mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text("Message sent successfully")),
          );
        }
        print(response.body);
      } else {
        print('Failed to send notification: ${response.body}');
      }
    } catch (e) {
      print('Error occurred while sending notification: $e');
    }
  }


Future<void> makeFakeCallInComing(String callerId) async {

  {
    _currentUuid = const Uuid().v4();

    final params = CallKitParams(
      id: _currentUuid,
      appName: 'VideoSdk',
      avatar: 'https://i.pravatar.cc/100',
      handle: "VideoSdk",
      type: 0,
      duration: 30000,
      textAccept: 'Accept',
      textDecline: 'Decline',
      missedCallNotification: const NotificationParams(
        showNotification: true,
        isShowCallback: true,
        subtitle: 'Missed call',
        callbackText: 'Call back',
      ),
      extra: <String, dynamic>{'userId': '1a2b3c4d'},
      headers: <String, dynamic>{'apiKey': 'Abc@123!', 'platform': 'flutter'},
      ios: const IOSParams(
        iconName: 'CallKitLogo',
        handleType: '',
        supportsVideo: true,
        maximumCallGroups: 2,
        maximumCallsPerCallGroup: 1,
        audioSessionMode: 'default',
        audioSessionActive: true,
        audioSessionPreferredSampleRate: 44100.0,
        audioSessionPreferredIOBufferDuration: 0.005,
        supportsDTMF: true,
        supportsHolding: true,
        supportsGrouping: false,
        supportsUngrouping: false,
        ringtonePath: 'system_ringtone_default',
      ),
    );
    await FlutterCallkitIncoming.showCallkitIncoming(params);
    Future.delayed(const Duration(seconds: 10), () async {
      await FlutterCallkitIncoming.endAllCalls();
      // _initializePhoneAccount();
    });
  }
}

To get entire code for home.dart file you can refer here.

Note: The above code is only applicable when app is in Foreground state or when app is open in Background, yet working on the case where app is totally terminated

App Reference

Conclusion

With this, we've successfully built the Flutter iOS video calling app using the Flutter_callkit_incoming package, VideoSDK, and Firebase, Node js. For additional features like chat messaging and screen sharing, feel free to refer to our documentation. If you encounter any issues with the implementation, don’t hesitate to reach out to us through our Discord community.

In today’s connected world, building a seamless video calling experience is more important than ever. If you're looking to create a cross-platform video calling app with native call-trigger functionality—just like a regular phone call—you’re in the right place.

In this tutorial, we’ll walk through building a powerful video calling app using:

• Flutter for the cross-platform UI
• Node.js for handling server-side token generation
• Firebase for real-time user status and call event synchronization
• VideoSDK for high-quality, low-latency audio and video communication
• Android’s Telecom Framework to provide native call UI and call management behavior

By the end, you’ll have a production-ready video calling experience complete with incoming/outgoing call screens, call controls, and real-time updates. Be sure to check out the sample code and demo video to see the final result in action.