Senior Java Developer Warsaw

Location: Warsaw!
Start: as soon as possible
Duration: long-term
Languages: Polish is mandatory !! English: B2

Project domain: telecommunication

Hybrid: 1-2x week in Warsaw | 5+ years Java exp | English B2+
 

• Backend Core: Expert-level Java 21+ (Virtual Threads, Records) and Spring Boot 3.x production proficiency.
• Reactive & Security: Spring WebFlux/WebClient for non-blocking I/O; Spring Security with OAuth2/JWT validation.
• Event-Driven Architecture: Designing high-scale ecosystems with eventual consistency, idempotency, and process orchestration.
• Migration Leadership: Leading domain-specific transitions from Java to Node.js/TypeScript (Key Differentiator).
• API Design: Contract-first development with OpenAPI 3.x and automated client generation.
• Database & State: Spring Data MongoDB (document modeling) and distributed state handling with Redis/Caffeine.
• Observability: Micrometer, Prometheus, and OpenTelemetry for distributed tracing and post-mortem analysis.
• Resilience: Advanced Resilience4j implementation (retries, backoffs, rate limiting, and graceful degradation).
• Testing & Tooling: Spock/Groovy (BDD), WireMock, and Maven multi-module management.