Senior Node.js developer for scalable backend systems
Based in Wroclaw, Poland · EU timezone · Available for new projects
I build backend systems in Node.js that handle real production load. APIs, microservices, event-driven architectures, WebSocket servers — whatever the business logic demands. Over 10 years of experience turning messy requirements into clean, maintainable backend code.
REST and GraphQL APIs
Production-grade API servers with proper authentication, rate limiting, validation, and documentation. Built with Express, Fastify, or NestJS depending on the project complexity and team preferences.
Microservices architecture
Decomposing monoliths into focused services communicating over message queues (RabbitMQ, SQS) or event streams (Kafka). Service discovery, circuit breakers, and distributed tracing included.
Real-time platforms
WebSocket servers for chat, live notifications, collaborative editing, and real-time dashboards. Socket.IO or raw WebSockets with proper connection management, reconnection logic, and horizontal scaling.
Third-party integrations and data pipelines
Connecting payment providers, CRMs, ERPs, shipping APIs, and other third-party services. Handling webhooks, retry logic, data transformation, and sync between systems that don't speak the same language.
Background jobs and task queues
BullMQ for job scheduling, email dispatch, PDF generation, data imports, and other async workloads. Proper retry policies, dead letter queues, and monitoring for long-running processes.
API design and architecture
RESTful conventions, versioning strategies, pagination patterns, error handling standards. I design APIs that other developers actually enjoy consuming — consistent, predictable, and well-documented with OpenAPI specs.
Event-driven architecture
Message brokers (RabbitMQ, SQS, Kafka) for decoupled services. Event sourcing and CQRS when the domain complexity justifies it. Idempotent consumers, dead letter handling, and exactly-once processing patterns.
Database layer
PostgreSQL with Prisma or Drizzle ORM. Query optimization, migrations, connection pooling, and read replicas. Redis for caching, sessions, and pub/sub. MongoDB when the data model fits.
Authentication and security
JWT, OAuth 2.0, session management, RBAC, and API key strategies. Input validation with Zod, SQL injection prevention, rate limiting, and security headers. I follow OWASP guidelines, not just the happy path.
Observability and monitoring
Structured logging with Pino, distributed tracing with OpenTelemetry, metrics with Prometheus. Health checks, alerting thresholds, and dashboards that tell you what's actually wrong at 3 AM.
Performance and scaling
Profiling event loop lag, identifying memory leaks, optimizing database queries. Horizontal scaling with PM2 or container orchestration. Load testing with k6 to find breaking points before users do.
System design
I map out the data flow, service boundaries, and integration points before writing code. We agree on API contracts, database schema, and deployment topology upfront.
Build with tests
I write the tests alongside the code. Integration tests for API endpoints, unit tests for business logic, contract tests for service boundaries. Every PR is reviewed and tested in a staging environment.
Deploy and monitor
Production deployment with health checks, structured logging, and alerting from day one. Your team gets runbooks, API documentation, and a system they can operate confidently.
Node.js excels at I/O-heavy workloads: APIs, real-time features, microservices, and integrations. It's the wrong choice for CPU-heavy computation (video encoding, ML inference). For most web applications and SaaS products, Node.js is an excellent backend choice.
Both. For enterprise-grade backends with complex domain logic, I use NestJS — it provides structure, dependency injection, and testing patterns that pay off at scale. For simpler APIs or microservices, Express or Fastify is leaner and faster to ship.
Yes. I regularly join projects mid-flight — fixing architecture issues, adding features, migrating from JavaScript to TypeScript, or refactoring monoliths into services. I start with a codebase audit so we prioritize the highest-impact work.
PostgreSQL is my default. I design normalized schemas, handle migrations with Prisma or Drizzle, and optimize queries with proper indexing and connection pooling. For caching and real-time features, I add Redis.
Yes. Docker containers on AWS (ECS, Lambda), Google Cloud Run, or Railway. I set up CI/CD pipelines, environment management, health checks, and monitoring. You get a fully operational production system, not just code in a repo.
I work on a daily or monthly rate depending on the engagement. Book a free 30-minute call and I'll give you an honest estimate based on your project scope.
Ready to hire a senior Node.js developer?
Book a free 30-minute technical call. I'll review your requirements and tell you honestly if I'm the right fit.