Senior Java Backend Engineer - iGaming Platform

We are expanding a backend engineering team building a new international gaming platform from the ground up.

The system sits close to the transactional core of the product: player accounts, wallet operations, payment flows, third-party integrations and services that must remain reliable under high traffic and failure conditions.

We are looking for a senior Java engineer who is comfortable taking ownership beyond individual tickets. You should be able to understand a business flow, design a robust backend solution, discuss trade-offs with other engineers and stay involved through implementation and production readiness.

This is a greenfield environment, so there is still real room to influence how services, integrations and engineering practices are designed.

• Backend services supporting player, account and wallet operations.
• Payment and transaction-related flows.
• REST APIs and service-to-service integrations.
• Event-driven components and asynchronous processing.
• Integrations with external gaming, payment and platform providers.
• Failure handling, retry and recovery mechanisms.
• Services designed for high availability and horizontal scale.
• Production-ready components with monitoring and operational visibility built in.

• Develop backend services using modern Java and Spring Boot.
• Turn product and domain requirements into maintainable technical solutions.
• Design APIs, events and integration contracts.
• Work with Kafka-based messaging and distributed workflows.
• Contribute to architecture and technical design decisions.
• Think explicitly about consistency, failure scenarios, retries and recovery.
• Work closely with backend engineers, QA, product and other stakeholders.
• Participate in code review and engineering-quality practices.
• Support services through testing, deployment and production readiness.
• Take ownership of the areas you build rather than treating development as ticket execution only.

• Backend

  Java 17–21+, Spring Boot 3, REST APIs, microservices

• Messaging

  Kafka, asynchronous processing, event-driven architecture

• Data

  PostgreSQL, SQL, transactional data models

• Platform

  Docker, Kubernetes, AWS

• Engineering

  CI/CD, automated testing, code review, production ownership

• Observability

  OpenTelemetry, Prometheus, Grafana or equivalent tooling

• Architecture

  Distributed systems, high availability, integration patterns, failure and recovery design

• At least 4 years of commercial backend development experience.
• Strong practical Java knowledge.
• Commercial experience with Spring Boot.
• Good understanding of microservices and distributed systems.
• Experience designing and consuming REST APIs.
• Practical experience with Kafka or another messaging platform.
• Solid SQL and relational database knowledge.
• Experience with production-grade applications.
• Familiarity with Docker and modern CI/CD practices.
• Ability to investigate technical problems independently and take ownership of solutions.
• Very good English communication skills.
• Fluent or professional working proficiency in Polish.
• Availability to work remotely from Poland and participate in workshops in Kraków when required.

• iGaming, sportsbook or online casino platforms.
• Payments or fintech.
• Wallets, ledgers or transaction-processing systems.
• High-volume e-commerce or marketplace platforms.
• Complex integrations with external providers.
• High-availability systems.
• Kubernetes in production.
• AWS or another major cloud platform.
• Kotlin or Scala.
• Observability tooling such as OpenTelemetry, Prometheus or Grafana.

• A genuinely greenfield product rather than maintenance of a legacy platform.
• Real influence on backend design and technical decisions.
• Work on challenging transaction, integration and reliability problems.
• A modern JVM, messaging and cloud engineering environment.
• Collaboration with experienced engineers in an international project.
• Remote work from Poland.
• An initial project workshop in Kraków and occasional follow-up workshops.
• B2B cooperation based on clear terms and ownership.
• Practical use of carefully selected AI tools to support engineering quality and delivery.
• A recruitment process focused on relevant engineering conversations rather than unnecessary stages.

We are not looking for someone whose Java experience stops at implementing another CRUD endpoint.

The right person thinks about what happens when a dependency is unavailable, an event is delivered twice, a transaction is interrupted or traffic increases sharply.

You enjoy understanding the full business flow behind a service, can make sensible engineering trade-offs and are comfortable taking responsibility for production-quality backend systems.

Experience in gaming or payments is valuable, but strong experience with other high-volume transactional platforms can be equally relevant.