Senior Backend Developer - Java and Spring Boot

Senior Backend Developer (Java / Spring Boot) About Sim Local Sim Local is a leading global travel eSIM provider, helping millions of travellers stay connected in over 200 destinations worldwide. Through a combination of local operator partnerships, innovative digital products, and omnichannel distribution, we deliver seamless connectivity experiences for international travellers. We're looking for a Senior Backend Developer with a strong track record of delivering production services and APIs end to end. You'll own backend services and API implementation across our multi-tenant, multi-brand eSIM and travel SIM platform, with real influence over architecture and technical decisions. Your work will power our D2C website and mobile app, our white-label partner stores, our internal platform, and the Networks and payment integrations behind them. Our stack: Java 17+, Spring Boot, Maven, MySQL, JPA/Hibernate, Liquibase and AWS (SQS/SNS, Lambda, Cognito, SES, CloudFormation). Key Responsibilities Backend Services & APIsDesign, build and ship backend services and APIs across our platform — customer-facing APIs, internal back-office systems, and partner integrationsBuild, maintain and scale our Java / Spring Boot services and API gateways, keeping them secure and reliable in production Third-Party IntegrationsBuild and maintain integrations with networks, payment or 3rd party providers, including webhooks and event-driven flowsDesign for failure — idempotency, retries and graceful handling of errors across distributed systems Architecture, Code Quality, Incident managementContribute to architecture decisions and help shape the technical direction of the platform as it scalesIdentify and resolve performance bottlenecks and security vulnerabilities before they reach productionReview code — including AI-generated code — and raise the bar for quality, testability and security across the teamChampion automated testing, clear API documentation and good engineering habitsOwn the services you build in production, using observability and monitoring to keep them fast, efficient and secure at scalePartner with platform engineering on infrastructure, deployments and incident resolution Team CollaborationWork with the Product Owner, developers and technical leaders to deliver focused, value-driven changes to the highest standardContribute to planning, agile ceremonies and continuous improvement of how the team works What We're Looking For Essential – All Candidates Bachelor's degree in computer science or other relevant discipline or equivalent work experience.4+ years of backend development experience, with a proven track record of delivering production services end to end2+ years experience building RESTful APIs and web services.Strong Java (17+) and Spring Boot, including Spring Security / OAuth2 and multi-module Maven projectsRelational databases (MySQL or similar), JPA/Hibernate and schema migration tools such as Liquibase — including schema design and query optimisation at scaleCloud-native services on AWS — SQS/SNS, Lambda, Cognito, SES, and CloudFormation or similar infrastructure-as-codeAsynchronous, message- and event-driven architectures, including distributed systems patterns such as idempotency and retry handlingAutomated testing — unit testing with JUnit and Mockito, and integration testing with Testcontainers or equivalentObservability and monitoring with APM tooling (Datadog, New Relic, CloudWatch or similar)Hands-on use of Claude Code or similar AI coding assistants, with the judgement to review, correct and take full ownership of AI-generated codeStrong code review skills and a track record of raising the bar for code quality across a teamCaching strategies and high-traffic, high-concurrency systems (e.g. Redis)Integrating third-party APIs and webhooks — payment providers, telecom/carrier providers, or CRM/marketing platformsExperience in a cross-functional Scrum team using Jira and Confluence Desirable API documentation with OpenAPI / SwaggerBackground in telecom, eSIM, travel or e-commerce Personal Qualities Strong delivery focus — takes ownership from design through to productionProactive — spots improvements and feels empowered to drive themMaintains and defends high engineering standards with good practices and habitsCollaborative, clear communicator with product and non-technical stakeholdersPassionate about development and eager to keep learning What We Offer Fully remote or hybrid — join the team in our Dublin 16 office whenever you like, or skip the long commuteCompetitive salary, depending on experience21 days' annual leave, plus an extra day for each complete year worked, up to 25 days per yearSummer Fridays — half days on Fridays throughout the summerPension schemeReferral schemeMaternity benefit This is a fantastic opportunity to join a company that cares about its people, likes to promote talent from within, and is continually growing in new markets. If you don't have all the requirements but this could be the right role for your career, apply for this position. We are looking for the best cultural fit. To apply for this position please forward your CV to: Careers@simlocal.com with the subject "Sim Local - Senior Backend Developer".