Onsite Full Stack Engineer (Node.js / React) – Fintech 🚀
Must-have:TypeScriptJavaReactNode.jsDockerFrontendBackendFullstackFinTechSenior
About the company
At ArrowFin, we support the construction and optimization of high-performance technology solutions that power our clients' trading activities directly on the Chicago Mercantile Exchange (CME). We develop our own software—no outsourcing or third-party client work—backed by an engineering team focused on real-time systems and distributed architecture.
Your tasks
We are hiring an Onsite Mid-Level Full Stack Engineer (Node.js / NestJS + React) for our office in El Poblado, Medellín. You will ship production code for our real-time trading products, working closely with senior engineers who will support your growth.
- Full Stack Development: Build and maintain backend services and REST APIs with Node.js, TypeScript and NestJS, and modern frontend interfaces with React and TypeScript.
- Quality: Write unit, integration and E2E tests as part of every deliverable, and take part in code reviews.
- Data & Real-Time: Write efficient PostgreSQL queries and migrations, respect multi-tenant data isolation, and work with WebSocket-driven UI updates.
- Collaboration: Turn technical specs into working features, raise blockers early, and help troubleshoot staging and production issues with the team.
Requirements
Hard Requirements
- Location & Language: B2 or higher English proficiency. Based in or around Medellín, or open to relocating (onsite role).
- Experience: 2–4 years of professional full stack web development.
- Backend: Solid experience with Node.js and TypeScript, ideally with NestJS (REST APIs, modules, dependency injection, guards and pipes).
- Frontend: Strong React + TypeScript skills, plus hands-on experience with React Router and TanStack (Query / Table / Router).
- Database: Working knowledge of PostgreSQL (queries, indexing basics, migrations with Prisma, TypeORM or Flyway).
- oTesting: Habit of writing tests (Jest/Vitest, Supertest, React Testing Library; Playwright is a plus).
Nice to Have
- Experience with Java and Spring Boot. We run a polyglot backend and some services use Spring.
- Exposure to WebSockets or event-driven systems.
- Familiarity with Clean / Hexagonal Architecture.
- Background in Fintech, trading, or other regulated environments.
- Docker and basic observability tooling (Grafana, Prometheus).