Senior Java Backend Developer

GR8_TECH builds B2B iGaming platforms for operators who play to lead. We deliver full-cycle, high-impact tech designed to scale — from seamless integrations and expert consulting to long-term operational support. Our platform powers millions of active players and drives real business growth. Call it what it is: the iGaming Platform for Champions. With 1000+ GR8 people across locations and time zones, we don't just ship technology — we help operators build success stories across brands, markets, and geos. Our ambition drives us. Our people make it real. If you're a challenger in spirit and a champion in action — join us. Why this role exists: This role exists to design, build, and maintain backend services across the Casino platform — bonus and promotional mechanics, wallet and transaction flows, game launch and catalog, and game provider integrations — ensuring reliability, correctness, and performance under high load. What you'll drive: Casino platform services Design and develop Spring Boot microservices across the casino domain: bonus processing, game launch, lobby and game catalog management.Implement and evolve promotional mechanics end-to-end — from bonus crediting and wagering logic to expiry and settlement — with correctness guarantees on real money.Integrate third-party game providers, game launch, wallet callbacks (bet/win/refund), provider-side bonus features.Build and evolve REST APIs consumed by internal services and external providers, including request signing, authentication, and API versioning. Reliability & correctness Ensure correctness of real-money transaction and bonus flows — idempotency, retries, timeouts, graceful degradation of downstream calls.Work with Redis for caching and session state; tune service performance under production load.Own observability: metrics (Micrometer/Prometheus, Grafana dashboards), structured logging, alerting. Quality & delivery Write and maintain unit, integration, and functional tests (JUnit 5, Testcontainers).Ship via GitLab CI to Kubernetes; participate in code review and incident investigation. What makes you a GR8 fit: Must-have 5+ years of experience in back end.Commercial experience with strong proficiency in Java (17+) and Spring Boot 3.x (Web, Security, Data, Actuator).Experience building business-critical domain logic (payments, bonuses, billing, or similar money-adjacent flows).Solid experience integrating third-party REST APIs and designing your own.Understanding of distributed systems basics: idempotency, consistency, timeouts, retries, caching.Experience with SQL and at least one NoSQL store (Redis, Cassandra, or Elasticsearch).Upper-intermediate or higher level of English. Nice-to-have Scala experience (parts of our wallet platform run on Scala / Play / Akka).Experience with Kafka and event-driven architectures (some of our services use Spring Cloud Stream).Experience running services on Kubernetes; familiarity with GitLab CI.Familiarity with Prometheus and Grafana.iGaming / betting domain experience. Why you'll love working here: Benefits Cafeteria — annual budget you allocate to: Sports Medical Mental health Home office Languages. Work-life & support Paid maternity/paternity leave + monthly childcare allowance.20+ vacation days, unlimited sick leave, emergency time off.Remote-first + tech support + coworking compensation.Team events (online/offline/offsite).Learning culture with internal courses + growth programs. Our culture & core values: GR8_TECH culture is how we win — through trust, ownership, and a growth mindset. We move fast, stay curious, and keep it real, with open feedback, room to experiment, and a team that's got your back. FUELLED BY TRUST: we're open, honest, and have each other's backs. OWN YOUR GAME: we take initiative and own what we do. ACCELER8: we move fast, focus smart, and keep it simple. CHALLENGE ACCEPTED: we grow through challenges and stay curious. BULLETPROOF: we're resilient, ready, and always have a plan.