Senior Backend Developer (M/F)
Senior backend developer at Roundtable, a fintech startup building co-investment infrastructure for private equity. Day to day: evolving a precision cap-table engine, designing atomic financial workflows, and scaling a Node.js/TypeScript stack (PostgreSQL, Prisma, tRPC, Redis, GCP) within a 10-engineer team, hybrid from Paris or Toulouse.
- Compensation
- €78K–€90K / yr
- Location
- Paris, France
- Work setup
- Not specified
- Seniority
- Senior
- Employment
- Not specified
- Experience
- 5+ years
- Category
- Backend
- Posted
Skills
Must have
- 5+ years of experience in Node.js/TypeScript
- Precision mindset: cares about decimal precision and idempotency in financial systems
- Pragmatic architecture: business-driven code structure, clear boundaries, readability
- Product-minded engineering: ownership of features and collaboration with product stakeholders
Nice to have
- Domain curiosity about private equity
- Background in finance or fintech
- Ideally has seen a startup grow
Full description
The Challenge: Building the “Gold Standard” for Private Equity
Private Equity is the last frontier of finance still running on Excel and fragmented processes. At Roundtable, we are building the infrastructure that allows thousands of investors to co-invest with surgical precision.
You’ll join a 10 engineer senior full-stack team organized in 2 squads, and you’ll be part of opening a third one. You’ll work closely with 2 product managers and be directly supported by our CTO and CPO, both founders.
Your Mission
You won’t just be “coding features.” You will be solving domain-driven puzzles where errors aren’t an option:
- Zero-Loss Engineering: Evolve our Cap Table engine to track ownership across thousands of investors with absolute precision (no rounding errors, no “lost cents”).
- Atomic Financial Workflows : Design atomic transitions for complex, multi-jurisdiction financial operations. Every state change must be auditable and reversible.
- Architecting for Scale: Help us transition our domain-driven architecture to handle 10x the current volume while maintaining 100% type safety.
- Production-Grade Engineering: Own the full reliability stack, from distributed tracing and structured observability to AI-assisted document pipelines. You’ll work on systems where understanding what happens in production is as important as what happens in code
Core Stack
- Core: Node.js, 100% TypeScript (Strict mode, no any).
- Data: PostgreSQL + Prisma, Redis (BullMQ for critical job queues).
- API & Communication: tRPC (with Zod) for end-to-end type safety from the database to the frontend.
- Ops: GCP, Turborepo, OpenTelemetry, Datadog.
- Quality: Vitest, Playwright, Zod (runtime validation at all boundaries).
You are a great match if:
- Experience: 5+ years in Node.js/TypeScript. You’ve ideally seen a startup grow
- Precision Mindset: You understand that in fintech, a bug isn’t just a ticket; it’s a financial consequence. You care about decimal precision and idempotency.
- Pragmatic Architecture: We don’t follow a named architecture style. We structure our code around business logic, clear entry points, explicit boundaries, and readability by anyone on the team. We care about code that makes sense, not code that follows a manifesto.
- Product-Minded Engineering: You don’t just “write tickets.” You understand the business logic behind the code and take ownership of the features you build. You enjoy collaborating with product stakeholders to ensure the technical solution perfectly serves the user experience.