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 processing, email, and cloud file storage
• Manage data changes: Write and update database migration scripts and investigate data-related production issues carefully against live data
• Partner with QA and product: Answer testers’ questions, clarify expected behavior, help reproduce issues, and support verification so fixes and features can be signed off smoothly. Ask product clarifying questions early and confirm intent and edge cases
• Improve observability and documentation: Contribute structured logging, masking of sensitive data, and clearer production visibility, and take part in code review while keeping documentation current as the platform grows

Required qualifications

• Proven ability to take ownership of a problem from start to finish, from initial bug report or change request through to a tested, deployed solution
• Production experience building and maintaining backend services with Node.js and TypeScript
• Strong experience with NestJS (or a comparable structured backend framework), including modules, controllers, services, dependency injection, and middleware
• Solid REST/HTTP fundamentals, including service-to-service communication, API contracts, versioning, and error handling
• Comfortable with relational databases, writing and reviewing PostgreSQL queries, and safe migration practices
• Experience debugging distributed systems where a single feature spans several services, reading logs and metrics to find root causes rather than symptoms
• Sound judgment about risk, including the difference between a safe local fix and a change that calls for a rollout plan, particularly for payments, authentication, and live data
• Experience integrating third-party systems (payment providers, CRMs, ERPs, identity providers) behind a clean internal interface
• Understanding of authentication patterns: OAuth 2.0, JWT verification, single sign-on (SSO), and service-to-service (machine-to-machine) authentication
• Comfortable with agentic development, using AI coding agents and tooling to investigate, build, and ship work efficiently while keeping a careful eye on quality
• Ability to write tests that confirm fixes and prevent regressions
• Excellent written and verbal communication, including clear status updates, incident notes, pull request descriptions, and documentation others can act on

Nice to have

• Experience supporting a platform through the transition from active build to maintenance-and-enhancement mode
• Familiarity with adapter patterns that isolate external systems from core business logic
• Experience with webhook-driven integrations, including verifying signatures, scoped service-to-service authorization, and safely handling repeated inbound events
• Familiarity with containers and orchestration (Docker and Kubernetes) and services deployed on a major cloud provider such as AWS
• Experience with observability practices such as structured logging and masking of sensitive data

All our positions are Remote and are available as Full Time Employment or B2B Contracts