Senior Software Engineer (Java) - Contract

Senior Software Engineer (Java) - Contract We are seeking a Backend Java Software Engineer to join our team on a contractual basis. This role heavily focuses on Java, Backend, iGaming Operator Integrations. This is 1 year extendable contract and applicants must operate through a fully registered limited company to be considered for this role. The role is fully remote, with occasional travel required to our headquarters in Málaga, Spain What You’ll Do Design, develop and maintain scalable, resilient backend services using Java (17+) and Spring Boot, with a strong focus on quality and a zero-defect mindset. Build and evolve integrations between our iGaming platform and operators, aggregators and other external partners. Design and implement robust REST APIs, asynchronous integrations and event-driven services supporting high-volume, real-time gaming transactions. Develop and maintain common platform capabilities supporting operator integration, including areas such as player sessions, authentication, wallet transactions, game launch, betting, settlement and transaction reconciliation. Work closely with Product, Architecture, Quality, Platform and fellow engineers to deliver solutions that meet immediate business needs while remaining scalable, maintainable and resilient. Understand external operator APIs and specifications, translating them into reliable platform integrations while identifying technical risks and integration dependencies early. Diagnose and resolve complex integration and production issues across distributed systems, APIs, messaging, databases and external dependencies. Design for failure through appropriate timeouts, retries, idempotency, error handling, observability and graceful degradation. Build quality into software from the outset by maintaining strong automated test coverage across unit, component, API and integration testing, ensuring appropriate tests are delivered as part of every change rather than added retrospectively. Develop and maintain automated API and integration tests using Playwright with TypeScript, or equivalent modern automation frameworks, to validate operator integrations and critical platform journeys. Collaborate closely with Quality Engineers while taking shared ownership of quality, ensuring testing and automation are embedded throughout the software development lifecycle. Contribute to CI/CD, deployment automation, monitoring and observability to ensure services can be safely deployed and effectively operated in production. Take ownership of software throughout its lifecycle, from design and implementation through deployment, monitoring and production support. Use AI-assisted engineering tools and practices to improve development productivity, code quality, testing and problem solving. Continuously improve code quality, engineering practices, developer experience and overall system design. What You’ll Bring Strong commercial software engineering experience with Java (17+) and Spring Boot or Quarkus. Strong understanding of backend and distributed-system design, including scalability, resilience, concurrency and high availability. Experience designing and consuming RESTful APIs and integrating with third-party or external systems. Experience with event-driven architectures and messaging technologies such as Kafka, Pub/Sub, RabbitMQ or equivalent. Good understanding of transactional systems and patterns such as idempotency, retries, duplicate handling, eventual consistency and failure recovery. Experience working with relational and/or NoSQL databases and diagnosing performance or data-related issues. ·Hands-on experience with cloud platforms, ideally GCP, and technologies such as Docker and Kubernetes. Good knowledge of CI/CD pipelines, deployment processes and production troubleshooting. Experience with observability practices including logging, metrics, tracing, alerting and service-health monitoring. Strong practical experience with unit, component, API and integration testing, with a demonstrated habit of delivering comprehensive automated test coverage alongside production code. Experience with Playwright and TypeScript for API/integration test automation, or strong experience with comparable automation frameworks and the ability to quickly adopt Playwright. Strong understanding of testability, mocking/stubbing, contract testing, test data management and effective test isolation. Experience with engineering practices such as TDD, BDD and pair programming, with a strong focus on code quality, maintainability and collaboration. A shift-left quality mindset, where engineers take ownership of preventing defects rather than relying on downstream testing to identify them. Strong debugging and problem-solving skills, particularly across distributed systems and external integrations. Experience using AI-assisted development tools as part of the software development lifecycle; experience creating reusable AI tooling, workflows or agents is advantageous. Excellent communication, planning and collaboration skills, including the ability to work effectively with technical and non-technical stakeholders. Fluent business English. ·A pragmatic, delivery-conscious mindset with the ability to balance speed, quality, resilience and maintainability. iGaming Experience – Highly Desirable Previous experience working within the iGaming, online casino, sportsbook or gambling technology industry. Experience integrating gaming platforms with operators, aggregators, wallet platforms or third-party gaming providers. Understanding of common iGaming integration flows such as player authentication, game launch, wallet/balance, bet, win, rollback/cancellation and transaction reconciliation. Experience working with real-money transactional systems, where correctness, traceability and reliability are critical. Awareness of the regulatory, security and operational considerations associated with real-money gaming platforms. Soft Skills Excellent communication and teamwork skills. Strong analytical and critical-thinking abilities. Ownership mindset with a willingness to take responsibility for services through to production. Self-motivated and comfortable working autonomously while collaborating effectively within a team. Positive growth mindset, adaptability and willingness to learn new technologies and domains. Comfortable working with external partners and navigating ambiguity during complex integrations. Strong attention to detail, particularly where transactional correctness and customer impact are concerned. Locations London Remote status Fully Remote About Expenti We're digital innovators, leveraging the latest tech to deliver solutions that drive engagement, supercharge efficiency and create unstoppable growth. It's our mission to push the envelope and build products that redefine what's possible. Epic experiences. Exceptional quality. That's Expenti.