JAKUB MIKULICA

Bochnia, Poland
https://www.linkedin.com/in/jakub-m-882b2a355/
jakubmrozik25@gmail.com

JavaScript | Frontend Developer

SUMMARY

Detail-oriented Frontend Engineer with extensive experience in building responsive user interfaces using
React.js, React Native, and Next.js. Adept at translating design mockups into high-quality code and ensuring
an optimal user experience. Strong background in modern frontend tooling, with a passion for continuous
learning and adaptability in fast-paced environments.

SKILLS

 JavaScript (ES6+)  Firebase

 TypeScript  Supabase
 React.JS  Redis
 Next.JS  AWS
 Nest.JS  GCP
 Electron  Nginx
 Microservices architecture  Ubuntu
 Jest  Asana PMS
 Playwright  Custom LLM integration
 Docker  Automation
 Kubernetes  Git

EXPERIENCE

ASYS

Frontend Engineer 08/2022 to 2/2025

 Architected a scalable booking system using Next.JS (App Router) for the frontend and Nest.JS for the
backend, enabling users to book, reschedule, and cancel appointments with real-time feedback and
availability sync.
 Structured and modularized the Next.JS codebase, organizing the project into feature-first folders and
reusable UI components for better maintainability and scalability.
 Upgraded the project from Next.JS 11 to 14, resolving legacy router conflicts and adopting the new
App Directory structure and Server Components for optimized rendering.
 Introduced NextAuth.JS for robust authentication, integrating with Supabase and supporting role-based
access control with custom session callbacks.
 Integrated Stripe, PayPal, and Apple Pay for secure payment processing, and connected RabbitMQ to
manage real-time messaging for booking confirmations and system-wide event triggers.
 Connected the app to AWS S3 for user-uploaded content (profile images, service assets), and used
CloudWatch for performance monitoring and alerting.
 Deployed services with Docker, configured Nginx for SSL termination and reverse proxy, and set up
CI/CD pipelines with GitHub Actions.
  Integrated with Vercel for frontend deployment and seamless GitHub integration, enabling instant
previews, staging branches, and auto-deploys.
 Optimized rendering strategy by balancing Server-Side Rendering (SSR) and Client-Side Rendering
(CSR) for booking flows, ensuring fast load times while preserving interactivity.
 Built a stream-based CRUD pipeline using MongoDB for efficient document processing.
 To optimize an existing database containing millions of records, developed a professional script and
implemented a CRUD module to streamline data management.
 Resolved system bottlenecks by configuring Nginx as a reverse proxy and implementing a micro-
services architecture, using Redis for session management to optimize Database access.
 Implemented real-time UI updates using WebSockets, connecting frontend booking components to
backend RabbitMQ event queues.
 Participated in agile ceremonies, contributing to sprint planning, daily stand-ups, and retrospectives.

KLEIO

Full Stack Developer 03/2019 to 07/2022

 Architected and developed a cross-platform application using React Native, allowing users to access
services on both iOS and Android devices.
 Developed and maintained web applications using React.js and Next.js, ensuring seamless integration
with backend services.
 Utilized TypeScript for enhanced code quality and maintainability in large codebases.
 Structured the entire React.JS project from scratch, ensuring long-term maintainability and a modular
architecture.
 Gained extensive experience with Stripe and mastered the integration of Stripe's payment gateway
within the project.
 Set up multiple web-hook endpoints in Stripe, Paypal and integrated them into the project.
 Developed a deep understanding of JavaScript promises, asynchronous programming, and non-blocking
architecture by working with multiple 6 third-party services in a single project.
 Built a chatbot to answer users’ questions regarding our services.
 Visualized insights using chart components in the React.JS front-end.
 Optimized database queries and schema to reduce database access time, and introduced Redis for
improved caching and performance.
 Configured main and subdomains using Nginx, SSL certificates, and private PEM files, managing QA,
development, and production environments.
 Assisted in the transition of legacy codebases to modern frameworks, enhancing maintainability and
scalability.
 Configured NGINX for routing external traffic to services with Kubernetes.

TENDANCES

Junior Developer 10/2016 to 1/2019

 Assisted in the development of web applications using HTML5, CSS3, and JavaScript, focusing on
responsive design principles.
 Supported the migration of legacy applications to modern frameworks, improving user experience and
performance.
 Developed a fully dynamic React.JS dashboard with 2D/3D charting (Chart.JS, Recharts, Three.JS),
featuring drilldowns, tooltips, data filters, and real-time rendering via React Suspense.
 Integrated Google Maps API for geolocation-based data insights, including clustering of bookings,
radius-based analysis, and interactive overlays.
  Implemented export functionality for filtered datasets to CSV, PDF, and AES-encrypted ZIP files,
supporting scheduled exports and secure sharing with external partners.
 Used Node.JS + Puppeteer to auto-generate PDF reports from dashboards; triggered via cron and
delivered via email or Slack.
 Introduced unit testing with Jest and React Testing Library across data processing and frontend logic,
achieving over 85% test coverage.
 Refactored data services into modular microservices using Docker + Kubernetes, reducing deployment
complexity and resolving API-level performance bottlenecks by over 60%.
 Automated reporting and Google Sheet syncing using Google Apps Script, creating daily digest sheets
for cross-functional team consumption.
 Built advanced scraper bots to detect changes in high-value listings, integrating anti-captcha bypass and
proxy rotation mechanisms for robust uptime.
 Deployed backend services and scrapers on both AWS EC2/S3/Lambda and GCP Cloud Functions
depending on workload, leveraging CloudWatch, GCP Logging, and Firebase Auth for monitoring and
access control.
 Created a visual query tool within the React dashboard, powered by Supabase functions, allowing
custom queries without SQL knowledge — saved business teams ~10 hours/week in manual reporting.

EDUCATION

BACHELOR OF SCIENCE IN COMPUTER SCIENCE

University College Dublin, Dublin, Ireland
June 2012 - September 2016