Node.JS / Nestjs Engineer

We partner with a US health‑tech company to take over a production AI mobile coaching platform (iOS, Android) with a microservices backend on AWS. You join the Polish team owning the BFF and supporting Node services during transition.

The pilot is a NestJS gateway integrating a Python AI core, a user‑profile service, a notifications service and third‑party tools (Auth0, OneSignal, Amplitude, Datadog).

Role summary

Senior Node Engineer / Deputy Tech Lead (BFF/Node): collaborate on architecture, enforce code quality, mentor mid‑level engineers, and take ownership of the gateway after knowledge transfer. ~70% hands‑on, ~30% leadership (code review, design, hiring, client talks).

First 90 days

• Read & document the BFF with the outgoing team
• Establish quality baseline: tests, TypeScript strictness, lint, deps, CI, flakiness
• Lead knowledge‑transfer sessions
• Identify high‑risk subsystems and propose stabilisation
• Define code‑review standards, branching model, definition of done

Ongoing

• Own BFF architecture and design reviews (esp. AI integration)
• Pair with and review mid‑level engineers
• Represent squad in cross‑team architecture talks
• Join on‑call rotation after take‑over

Offer:

• Location: 100% remote
• Engagement: B2B
• Rate: up to PLN 170–175 p/h
• Start: July

Must-have skills

• 5+ years Node.js in production, 3+ years NestJS
• Strong TypeScript — strict mode, generics, type narrowing, no any-as-escape-hatch
• NestJS depth: modules, providers, DI scope, guards, interceptors, pipes, custom decorators
• REST API design at scale; familiarity with BFF / API-gateway patterns
• GraphQL or schema federation comfort (not required to be primary stack)
• MongoDB in production — Mongoose or native driver, schema design, indexing
• Auth0 integration — both user authentication flows and Machine-to-Machine (M2M) client credentials
• AWS production experience — ECS or EKS, IAM, VPC, RDS, ElastiCache
• CI/CD on GitHub Actions
• Distributed tracing and structured logging in production environments
• Comfortable writing tests (Jest) and raising coverage on legacy code
• Code-review and mentorship experience

Nice-to-haves

• Datadog APM, log correlation, custom metrics
• WebSocket / WSS (the AI chat surface uses streaming)
• OpenAPI / Swagger contract-first workflows
• Prior gateway / aggregator / BFF role
• LangChain or LangGraph awareness (you won't write Python, but you will integrate with a Python AI service)
• Public-cloud cost-control habits