Senior Node.js / AWS / React Developer – Freelance

Project overview

As part of the development of a new technology platform dedicated to collecting audio data for training artificial intelligence models, our client is looking for a Senior Fullstack Developer with a strong backend focus on Node.js / AWS.

You will be involved in an innovative project, within a small team, with significant technical autonomy and responsibility for designing, developing, and evolving a web platform from end to end.

The objective is to internalize a platform currently spread across several tools, in order to centralize user registration, onboarding, session scheduling, audio recording, and collected data management.

Your main missions:

Profile sought

You have at least 10 years of experience in developing production web applications, with solid expertise in backend development and the ability to work across the entire stack.

You master the following technologies and environments:

Experience with the following technologies would be appreciated:

Beyond your technical skills, you are recognized for your autonomy, pragmatism, and ability to design robust solutions in a developing environment.

You enjoy projects where architectural decisions need to be made, new features need to be developed quickly, and their production deployment needs to be supported.

A good command of French and English is necessary to collaborate with the various teams.

Work environment

You will join a project with significant technical challenges, offering real autonomy in architectural choices and the opportunity to contribute directly to the construction of a new platform.

• Take over, maintain, and evolve an existing platform developed in TypeScript, React, and Next.js.
• Design and develop the backend architecture in Node.js on an AWS infrastructure.
• Develop an audio collection platform integrating session scheduling, participant management, and automated reminders.
• Design audio recording functionalities directly from the browser, with management of Web Audio, WebRTC, or MediaRecorder APIs.
• Implement mechanisms for uploading large audio files, with segmented transfer and resumption on interruption.
• Develop user registration, onboarding, contracting, and consent flows.
• Ensure the security, traceability, and confidentiality of collected data, particularly voice data.
• Design and maintain the AWS services necessary for data storage and security.
• Implement good development practices: testing, CI/CD, observability, documentation, and performance monitoring.
• Participate in the analysis of user journeys and the optimization of conversion and completion rates.
• Collaborate with Product, Data, and Operations teams to transform business needs into concrete features.
• Backend: Node.js, TypeScript, API design, and backend architectures.
• Frontend: React, Next.js, web interface development.
• Cloud: AWS, particularly S3, IAM, and KMS.
• Infrastructure: Docker, Kubernetes, deployment, and production application diagnostics.
• Audio & Web APIs: WebRTC, Web Audio, MediaRecorder, or real-time communication SDKs.
• Quality & Observability: automated tests, CI/CD, logs, metrics, traces, and alerting.
• Security: access management, sensitive data protection, and traceability.
• LiveKit, mediasoup, Daily, or other WebRTC solutions.
• AudioWorklet, IndexedDB, Uppy, or offline-first architectures.
• Supabase, BullMQ, Graphile Worker, or Helm.
• Marketplace-type platforms integrating onboarding, scheduling, and payments.
• Environment: Small technical team, collaborating with Product, Data, and Operations teams
• Stack: Node.js, TypeScript, React, Next.js, AWS, Docker, Kubernetes, WebRTC
• Context: Development of an audio collection platform for artificial intelligence applications

Project details

• Start: ASAP
• Duration: 3 mois renouvelable
• Remote: hybrid
• Location: Paris, Île-de-France, FR
• Rate: 50-71 EUR/h
• Languages: French