Browse free open source API Gateways and projects below. Use the toggles on the left to filter open source API Gateways by OS, license, language, programming language, and project status.

  • Gen AI apps are built with MongoDB Atlas Icon
    Gen AI apps are built with MongoDB Atlas

    Build gen AI apps with an all-in-one modern database: MongoDB Atlas

    MongoDB Atlas provides built-in vector search and a flexible document model so developers can build, scale, and run gen AI apps without stitching together multiple databases. From LLM integration to semantic search, Atlas simplifies your AI architecture—and it’s free to get started.
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  • The All-in-One Commerce Platform for Businesses - Shopify Icon
    The All-in-One Commerce Platform for Businesses - Shopify

    Shopify offers plans for anyone that wants to sell products online and build an ecommerce store, small to mid-sized businesses as well as enterprise

    Shopify is a leading all-in-one commerce platform that enables businesses to start, build, and grow their online and physical stores. It offers tools to create customized websites, manage inventory, process payments, and sell across multiple channels including online, in-person, wholesale, and global markets. The platform includes integrated marketing tools, analytics, and customer engagement features to help merchants reach and retain customers. Shopify supports thousands of third-party apps and offers developer-friendly APIs for custom solutions. With world-class checkout technology, Shopify powers over 150 million high-intent shoppers worldwide. Its reliable, scalable infrastructure ensures fast performance and seamless operations at any business size.
    Learn More
  • 1
    Swagger UI

    Swagger UI

    HTML, JavaScript, and CSS assets that generate Swagger documentation

    Swagger UI is a collection of HTML, JavaScript, and CSS assets that dynamically generate beautiful documentation from a Swagger-compliant API. Simplify API development for users, teams, and enterprises with the Swagger open source and professional toolset. Find out how Swagger can help you design and document your APIs at scale. The power of Swagger tools starts with the OpenAPI Specification — the industry standard for RESTful API design. Individual tools to create, update and share OpenAPI definitions with consumers. SwaggerHub is the platform solution to support OpenAPI workflows at scale. Swagger open source and pro tools have helped millions of API developers, teams, and organizations deliver great APIs. Swagger offers the most powerful and easiest to use tools to take full advantage of the OpenAPI Specification.
    Downloads: 61 This Week
    Last Update:
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  • 2
    OpenAPI Generator

    OpenAPI Generator

    OpenAPI Generator allows generation of API client libraries

    With 50+ client generators, you can easily generate code to interact with any server which exposes an OpenAPI document. Maintainers of APIs may also automatically generate and distribute clients as part of official SDKs. Each client supports different options and features, but all templates can be replaced with your own Mustache-based templates. Getting started with server development can be tough, especially if you're evaluating technologies. We can reduce the burden when you bring your own OpenAPI document. Some generators support Inversion of Control, allowing you to iterate on design via your OpenAPI document without worrying about blowing away your entire domain layer when you regenerate code. Ever wanted to iteratively design a MySQL database, but writing table declarations was too tedious? OpenAPI documents allow you to convert the metadata about your API into some other format.
    Downloads: 2 This Week
    Last Update:
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  • 3
    OpenAI-Java

    OpenAI-Java

    OpenAI Api Client in Java

    OpenAI-Java is the official Java client library provided by OpenAI for interacting with the OpenAI API. It is designed to make it easier for Java applications to call endpoints like chat completions, embeddings, function calling, streaming, and other model services using idiomatic Java patterns. You configure the client (often via environment variables or system properties), then build parameter objects (e.g. ChatCompletionCreateParams) and invoke methods like client.chat().completions().create(...) to send requests in a type-safe way. The library also supports streaming APIs, where the response arrives in chunks, using helpers like ChatCompletionAccumulator to accumulate partial responses into a full object. For complex use cases (e.g. structured outputs, function calling), it provides schema support, JSON annotations, and schema validation.
    Downloads: 1 This Week
    Last Update:
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  • 4
    whatsapp-api-client-python
    This library helps you easily create a Python application with WhatsApp API. https://green-api.com/en/
    Downloads: 1 This Week
    Last Update:
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  • Simple, Secure Domain Registration Icon
    Simple, Secure Domain Registration

    Get your domain at wholesale price. Cloudflare offers simple, secure registration with no markups, plus free DNS, CDN, and SSL integration.

    Register or renew your domain and pay only what we pay. No markups, hidden fees, or surprise add-ons. Choose from over 400 TLDs (.com, .ai, .dev). Every domain is integrated with Cloudflare's industry-leading DNS, CDN, and free SSL to make your site faster and more secure. Simple, secure, at-cost domain registration.
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  • 5
    Google APIs Node.js Client

    Google APIs Node.js Client

    Google's supported Node.js client library

    Google's supported Node.js client library for accessing Google APIs. Support for authorization and authentication with OAuth 2.0, API Keys and JWT (Service Tokens) is included. The full list of supported APIs can be found on the Google APIs Explorer. The API endpoints are automatically generated, so if the API is not in the list, it is currently not supported by this API client library. These client libraries are supported by Google. However, these libraries are considered complete and are in maintenance mode. This means that we will address critical bugs and security issues but will not add any new features. For Google Cloud Platform APIs, we recommend using google-cloud-node which is under active development. This library supports the maintenance LTS, active LTS, and current release of node.js.
    Downloads: 0 This Week
    Last Update:
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  • 6
    Got

    Got

    Human-friendly and powerful HTTP request library for Node.js

    Got implements RFC 7234 compliant HTTP caching which works out of the box in-memory and is easily pluggable with a wide range of storage adapters. Got uses Keyv internally to support a wide range of storage adapters. For something more scalable you could use an official Keyv storage adapter. Hooks allow modifications during the request lifecycle. Hook functions may be async and are run serially. Got will make no further changes to the request before it is sent. This is especially useful in conjunction with got.extend() when you want to create an API client that, for example, uses HMAC-signing. You can override the request function by returning a ClientRequest-like instance or a IncomingMessage-like instance. This is very useful when creating a custom cache mechanism. The response object will typically be a Node.js HTTP response stream, however, if returned from the cache it will be a response-like object which behaves in the same way.
    Downloads: 0 This Week
    Last Update:
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  • 7
    Swagger Core

    Swagger Core

    Examples, server integrations for generating Swagger API Specification

    Swagger Core is a Java implementation of the OpenAPI Specification. Current version supports JAX-RS2 (javax and jakarta namespaces). One of the common usage scenarios is to integrate swagger-jaxrs2 into an existing or new JAX-RS based project ("code-first"), to automatically provide and expose its APIs definition, which is kept in sync during the project lifecycle. Such definition can be the base for further processing/consumption, including API documentation (e.g with swagger-ui, API client generation in various languages (e.g with swagger-codegen), custom processing, and so on. Such result is achieved by scanning JAX-RS resources and resolving their operations and used types, (also) processing applied annotations (e.g. Swagger, JAX-RS, Jackson, JAXB, etc.). An extension mechanism allows to further customize and pre/post processing result.
    Downloads: 0 This Week
    Last Update:
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  • 8
    Vertopal PHP

    Vertopal PHP

    PHP library for Vertopal file conversion API

    Vertopal PHP is a PHP library for easy access to Vertopal file conversion API. Using Vertopal PHP, you can get started quickly and easily implement the support of converting +350 file formats into your project.
    Downloads: 0 This Week
    Last Update:
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  • 9
    WWW::Suffit::Client

    WWW::Suffit::Client

    The Suffit API client library

    This library provides methods for access to Suffit API servers
    Downloads: 0 This Week
    Last Update:
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  • Enterprise and Small Business CRM Solution | Clear C2 C2CRM Icon
    Enterprise and Small Business CRM Solution | Clear C2 C2CRM

    Voted Best CRM System with Top Ranked Customer Support. CRM Management includes Sales, Marketing, Relationship Management, and Help Desk.

    C2CRM consists of four modules that integrate to provide a comprehensive CRM solution: Relationship Management, Sales Automation, Marketing Automation, and Customer Service. Only buy what each user needs.
    Learn More
  • 10
    Web3 API for Haskell

    Web3 API for Haskell

    Web3 API for Haskell

    This library implements Haskell API client for popular Web3 platforms.
    Downloads: 0 This Week
    Last Update:
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  • 11

    email-checker-php-sdk

    PHP SDK to connect with Easy Email Verification API and validate email

    The Email Checker PHP SDK is part of the Easy Email Verification - URL Checker ecosystem, designed to help developers integrate real-time email verification into their PHP applications. It uses the Easy Email Verification API to validate if an email address is real, active, and safe to use. The SDK performs domain and MX record checks, SMTP validation, and detection of disposable or role-based addresses. It provides a lightweight and reliable cURL-based implementation that returns structured JSON responses. This project is officially maintained by Easy Email Verification Ltd. For technical documentation and API reference, visit https://www.easyemailverification.com
    Downloads: 0 This Week
    Last Update:
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