Senior Full-Stack Backend & Cloud Infrastructure

• Strong commercial experience with TypeScript and Node.js development
• Proven experience building and maintaining backend services using NestJS
• Experience with WebRTC data channels and peer-to-peer architectures
• Hands-on expertise with PostgreSQL, Redis, and modern API architectures
• Solid AWS experience, including ECS Fargate, RDS, ElastiCache, S3, and load balancers
• Experience with Infrastructure as Code, preferably AWS CDK in TypeScript
• Strong CI/CD knowledge, including GitHub Actions and multi-environment deployment pipelines, and cloud authentication mechanisms such as OIDC role assumption
• Production-focused mindset, including experience implementing observability and monitoring solutions, with a strong focus on scalability, security, and reliability.
• Experience writing automated tests and maintaining high-quality CI pipelines
• Good communication skills and ability to work across backend, infrastructure, and frontend domains
• Fluent English - C1 level

Nice to have:

• Experience with Playwright or similar end-to-end testing frameworks
• Knowledge of browser automation and CI stability improvements
• Familiarity with OAuth2, JWT authentication, refresh token rotation, and reuse detection
• C++ and Qt/QML familiarity, especially with Emscripten and CMake. Our viewer embeds a Qt engine compiled to WebAssembly, and an owner for that build pipeline is a big plus

This is a technically strong freelance opportunity that combines backend ownership with modern AWS infrastructure and real-time communication technologies.

Project description:

About the Product:

Our client is developing an innovative design-to-code platform that converts Figma designs into production-ready QML code for Qt Desktop and Qt for MCUs, with a live preview that renders the generated QML directly in the browser through a real Qt engine compiled to WebAssembly.

The solution includes a Figma plugin, a React-based live preview application, backend services, and a WebRTC signaling layer enabling fully peer-to-peer preview sessions.

Design data never touches our servers; getting that architecture right is part of what makes this role interesting.

You will own the server side of the product: two NestJS services and a React frontend, all deployed to AWS through CDK and GitHub Actions. The services recently moved from Heroku to AWS (ECS Fargate, ALB, RDS, ElastiCache, S3, Amplify), and you will inherit, run, and evolve that infrastructure.

Beyond infrastructure, this is a hands-on product engineering role: you will build backend features, improve the real-time WebRTC layer, and contribute to the viewer and plugin when features cut across service boundaries, which they often do.

Tech stack:

• TypeScript, Node.js 24, NestJS (Fastify), React 18
• PostgreSQL 17
• Vite
• Prisma
• Redis
• Socket.IO
• WebRTC
• AWS (ECS Fargate, ALB, RDS, ElastiCache, S3, Amplify), AWS CDK
• GitHub Actions, Docker
• Sentry
• Tailwind CSS
• C++17
• Qt 6 / QML
• WebAssembly (Emscripten)

,[Design, develop, and maintain backend services built with NestJS, Fastify, PostgreSQL, Prisma, Redis, and S3, Develop and enhance the WebRTC signaling server using NestJS, Socket.IO, and Redis, Own and evolve AWS infrastructure using CDK, including ECS Fargate, ALBs, RDS, ElastiCache, S3, and Amplify, Manage and improve CI/CD pipelines using GitHub Actions across development, staging, and production environments, Ensure platform reliability through monitoring, health checks, rate limiting, security controls, and observability practices, Implement and maintain distributed coordination mechanisms such as Redis-based locking for cron jobs running across multiple tasks, Improve WebRTC communication reliability, including connection handling, backpressure management, and chunked file transfers, Contribute to frontend development in React and collaborate on cross-functional product features, Build and maintain automated unit, integration, and end-to-end test suites, Optimize deployment workflows and support release automation processes, Collaborate with product and engineering teams to deliver scalable and high-quality solutions, Continuously improve platform performance, maintainability, and operational excellence] Requirements: TypeScript, Node.js, WebRTC, PostgreSQL, Redis, API, AWS, ECS, AWS ECS, AWS Fargate, Amazon RDS, ElastiCache, AWS S3, Infrastructure as Code, GitHub Actions, Cloud, Security, AWS CDK, CD, Playwright, Testing, Qt, QML, Emscripten, CMake, WebAssembly