Senior Fullstack Developer (React/Next.js/Node.js) for a solidarity association

Mission offered by Karma Com Solidarité throughout the Hauts‑de‑Seine department

Join our mission for digital solidarity

Mission offered by Karma Com Solidarité throughout France

Are you passionate about modern web development and do you want your code to serve a purpose that truly matters?

At Karma Com Solidarité (KCS), we build platforms that concretely help associations to better manage their projects, their volunteers, and their communication.

No more empty talk – every feature you deploy means an organization saves time, increases efficiency, and has a greater impact. And that's measurable!

About Karma Com Solidarité

Karma Com Solidarité is an association that strengthens the impact of non‑profit organizations through responsible communication and digital inclusion. We code for those who don't have the resources of an IT department, we train those who need it, and we create game‑changing tools.

Guided by values of solidarity, inclusion and transparency , we welcome senior and junior tech profiles (depending on the missions) who want to put their expertise at the service of the common good.

Your mission, should you choose to accept it!

As a senior full‑stack developer volunteer, you will be the technical lead for our web ecosystem (institutional websites + SaaS platforms for associations). You will code in React/Next.js, develop backend APIs in Node.js, coordinate with our DevOps team, and ensure that our applications are high‑performing, accessible, and deployed properly.

In this role, you will contribute your expertise to

• Develop modern full‑stack applications Next.js (App Router, Server Components, Server Actions), React with TypeScript, state management (Redux Toolkit, Context API)
• Design and maintain backend APIs Node.js with Express/Fastify, PostgreSQL/MongoDB/Redis databases, REST and GraphQL APIs (Apollo/Prisma)
• Implement authentication and security JWT, OAuth, NextAuth, security best practices (vulnerability scans)
• Set up CI/CD pipelines GitHub Actions/GitLab CI, build/deployment automation, environment management (dev/staging/prod)
• Containerize and deploy Docker, Docker Compose, cloud deployments (AWS EC2/S3/RDS, Vercel, Heroku)
• Ensure quality and performance automated testing (Jest, React Testing Library), Core Web Vitals optimization, monitoring
• Maintain clean and well‑documented code Git conventions (GitFlow, commits), constructive code reviews, clear technical documentation

Why join KCS?

Direct social impact

Your code will be used by 15‑20 organizations starting in 2026‑2027 to manage their volunteers, projects, and communications. Every line you write tangibly improves digital inclusion and the efficiency of organizations that change lives. We measure the impact, we see it, we celebrate it.

Structured & professional environment

We work with robust tools (GitHub, Figma, Notion, Slack, Docker, CI/CD), clear processes (kickoff, Definition of Done, regular reviews), and an expert team that supports you without micromanaging you. You'll have technical autonomy, but you'll never feel like you're alone against a wall.

Professional Development

Access to training relevant to the mission, technical exchanges with senior peers, and a portfolio of potentially open‑source projects (depending on negotiated licenses). And if you'd like a LinkedIn recommendation after 12 months of impeccable service, we'd be happy to provide it.

Freedom and recognition

You have complete freedom in making technical choices (within the overall architectural framework), your ideas matter, and your work is valued. We don't count the hours down to the minute, we count the results and the impact. And we say thank you when it's done well.

Kindly do apply with your updated resume to make the process fast.