Senior Java Developer

GR8 Tech; Deutschland; Remote; EUR 70.000 - 110.000; Vollzeit

Benefits dieser Stelle

Cafeteria/allowance

Remote-first work model

Team events

Learning culture

Zusammenfassung

GR8_TECH is seeking a senior backend engineer to design, build, and maintain microservices for our casino platform. You will implement bonus processing, game launch, and catalog features with a focus on reliability under high load.

Join a remote-first team working with Java 17+, Spring Boot 3.x, and modern DevOps tools. You will integrate third-party providers and ensure robust observability, testing, and scalable backend services across geos.

Qualifikationen

• 5+ years of backend development experience.
• Strong proficiency in Java (17+) and Spring Boot 3.x.
• Experience building business-critical domain logic (payments, bonuses, billing).
• Experience integrating third-party REST APIs and designing APIs.
• Understanding distributed systems concepts: idempotency, timeouts, retries, caching.
• Experience with SQL and at least one NoSQL store (Redis, Cassandra, Elasticsearch).
• Upper-intermediate or higher English.

Aufgaben

• Design, build and maintain backend services for the casino platform.
• Develop Spring Boot microservices for bonus processing, game launch and catalog management.
• Implement and evolve promotional mechanics end-to-end with correctness guarantees.
• Integrate third-party game providers and wallet callbacks.
• Build REST APIs for internal/external use with proper security and versioning.
• Ensure reliability via observability, metrics, logging, and alerting.
• Write unit/integration tests; ship via CI to Kubernetes; participate in code reviews and incident investigation.

Kenntnisse

Java (17+)

Spring Boot

Backend design

Distributed systems

SQL

NoSQL

English (professional)

Kubernetes

Kafka

Redis

Tools

GitLab CI

Kubernetes

Prometheus

Grafana

Redis

Kafka

Elasticsearch

Cassandra

Jobbeschreibung

Our Work

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

• 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.