S/03
Backend and API development
Secure, high-performance APIs and backend systems with NestJS or Spring Boot.
The part customers never see
Backend work decides whether a product stays reliable as it grows. I design APIs, data models and the business logic behind them.
On Qystra that meant a modular monolith with separate API and worker processes. On KliqueOS it meant multi-tenant data and replay-safe payment webhooks.
Good fit
- A new API for a web or mobile product
- Payments, subscriptions or background processing
- A backend that needs structure before it grows further
What you get
REST APIs with generated OpenAPI documentation
PostgreSQL schema design and migrations
Background jobs and queues
Real-time features over WebSockets
Payment webhooks and third-party integrations
Multi-tenant architecture