Senior Fullstack Engineer (TypeScript)

Who we areCryptoNext Security is a deeptech startup specializing in post-quantum cryptography. Our solutions help businesses and institutions prepare for a future where quantum computers will challenge traditional data security. We work with leading clients in finance, defense, and telecommunications. On a daily basis, you will•     Own features end to end in TypeScript: Hono and Node.js on PostgreSQL, React SPA on the front. •     Design HTTP APIs consumed through Hono's typed RPC client, with generated OpenAPI specs. •     Model and query PostgreSQL: schema, migrations, query performance. •     Build interfaces with Vite, TanStack, Tailwind and shadcn/ui. •     Work directly with Product and QA. •     Write the unit and integration tests that back your features, and give QA what they need to automate the rest. •     Review code. •     Use AI coding tools as leverage under your own judgement, staying accountable for what lands in the repo. •     Propose upgrades and refactorings, and explain the trade-offs you accepted. How we workA team of six engineers, within our 15-person R&D department. A single TypeScript monorepo, with shared types and tooling across services and front. Three days a week in our Paris office, the rest remote. Short feedback loops, high standards. We ship a working version early rather than polishing in isolation, and keep solutions as simple as the problem allows. Our products ship on-premise, sometimes into air-gapped environments, so builds have to be reproducible and dependencies deliberate. We build software our clients rely on for security: secure defaults, reviewed dependencies and tested code are part of shipping, not a later phase. We care more about a decision you can justify than a pattern you can name.