Senior Java Developer

About the role

As a Senior Java Developer at GR8 Tech, you will be instrumental in developing and evolving the core casino platform services. This includes designing and implementing Spring Boot microservices for bonus mechanics, game launch processes, and managing the game catalog. A key part of the role involves ensuring the precise and correct handling of real-money transactions and bonus flows, from crediting and wagering logic to expiry and settlement, requiring a keen eye for detail and correctness guarantees.

The position also involves significant integration work, connecting the platform with third-party game providers through robust REST APIs. You will be responsible for building and refining these APIs, incorporating security measures like request signing and authentication, and managing API versioning. Ensuring the reliability and performance of these services under production load is critical, utilizing tools like Redis for caching and session state management.

Success in this role means delivering high-quality, resilient backend services that power millions of active players. You will contribute to the entire development lifecycle, from writing comprehensive unit and integration tests to participating in code reviews and incident investigations. Your work will directly support the operational success of iGaming operators by providing scalable and high-impact technology solutions.

Skills that matter here

• Java: You will be developing backend microservices using Java 17+ for the iGaming platform.
• Spring Boot: This role requires proficiency in Spring Boot 3.x to design and implement casino domain services.
• REST APIs: You will be integrating third-party game providers and building internal APIs, focusing on authentication and versioning.
• SQL: Experience with SQL databases is required for managing persistent data within the platform services.
• NoSQL: You will work with at least one NoSQL store, such as Redis, for caching and session state management.
• Kubernetes: Familiarity with running services on Kubernetes is beneficial, as deployments are handled via GitLab CI.

Who this role suits

• A developer with a strong background in building business-critical, money-adjacent systems, such as payments or billing.
• Someone who prioritizes correctness and reliability, especially when dealing with real-money transactions and complex bonus logic.
• An individual who thrives in a fast-paced environment and is comfortable with distributed systems concepts like idempotency and consistency.
• A team player who actively participates in code reviews and contributes to maintaining high code quality and observability.

From the employer

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.