Full Stack Developer

About Us

We are a French company specializing in the development and operation of critical computing infrastructures, with a focus on hyperdense data centers dedicated to artificial intelligence.

Sesterce was built on a clear conviction: Europe needs sovereign, high-performance, and decarbonized AI infrastructure. In full growth mode, our mission is to design, build, and operate next-generation computing campuses across France and internationally. Our solutions power the most demanding AI workloads for leading clients in the industry.

To strengthen our Engineering team, we are looking for a versatile, quality-driven, and collaborative Full Stack Developer.

Your Responsibilities

Frontend Development

• Build modern, responsive, and accessible UIs with Next.js and React.js
• Implement UI components in collaboration with UX/UI designers (Figma, Storybook)
• Optimize front-end performance (Core Web Vitals, lazy loading, code splitting, SSR/SSG)
• Write frontend tests (Jest, React Testing Library, Cypress)

Backend Development

• Design and build RESTful APIs and backend services with Node.js
• Model and manage databases (MongoDB, MySQL, PostgreSQL)
• Implement authentication and authorization (JWT, OAuth 2.0)
• Secure APIs (input validation, rate limiting, error handling, logging)
• Build integrations with third-party systems (monitoring APIs, business tools)

Architecture & Quality

• Write clean, maintainable code following SOLID principles and proven design patterns
• Conduct constructive code reviews and participate actively in pull request processes
• Optimize applications for speed, scalability, and resilience
• Write technical documentation (API docs, architecture guides, READMEs)

Product & Collaboration

• Participate in sprint planning and backlog refinement
• Collaborate closely with product, design, infrastructure, and ops teams
• Monitor application performance in production

Your Profile

Education & Experience

• Bachelor's in Computer Science or equivalent
• Proven Full Stack experience with Node.js and Next.js

Technical Skills

• Proficient: JavaScript/TypeScript, HTML, CSS, React.js, Next.js, Node.js
• Databases: MongoDB, MySQL, PostgreSQL
• RESTful API design and Git (branching, PR workflows)
• Testing tools (Jest, Cypress) are a plus
• Blockchain/Web3 experience is a plus

Personal Qualities

• Quality-driven with a strong sense of ownership
• Collaborative, communicative, and comfortable in an agile environment

Languages

• English: professional level required
• French: a plus

Why Join Us?

• Build the web platform that powers Sesterce's GPU infrastructure and client experience
• Work end-to-end across the full stack: from pixel-perfect UIs to robust backend APIs
• Ship in a fast-moving startup where your code is in production and makes a real difference
• A tight-knit, demanding, and passionate team where every contribution matters
• Competitive package: salary based on profile, health insurance, transportation