Backend Nest.js Developer (Poland)

About the role We are seeking a proactive, technically strong Backend Developer to keep a live, business-critical microservices platform healthy while delivering meaningful improvements on top of it. This is a hands-on role with a high degree of autonomy: you’ll take a bug report or change request, investigate it across the codebase, and see it through to production. You’ll balance production support with feature engineering, backed by a supportive team, and we’re embracing agentic development with AI coding agents to ship efficiently without compromising quality. Key responsibilities Resolve production issues: Triage, diagnose, and resolve issues across distributed microservices, tracing a request from the user-facing API down to the services that talk to external systems. Support incident response: Investigate root causes, apply fixes, add regression tests, and document findings so issues don’t recur Deliver enhancements: Build improvements to existing services, including new versions of certification programs, scorecard and scoring changes, payment adjustments, and integration updates Work within the architecture: Follow established patterns and shared internal libraries in a layered service architecture, from the API gateway through the business logic services down to the adapters that integrate with external systems Maintain integrations: Maintain and extend integrations with external platforms for performance data, CRM, enterprise resource planning (ERP), payment proces