Top Java Developer Jobs in Belfast

Develop and support a full-stack reconciliation platform using Java, Angular, NoSQL, and Oracle. Responsibilities include designing features, analyzing code, implementing enhancements, troubleshooting vulnerabilities, testing fixes, advising stakeholders, coaching junior team members, and managing technical risks for global financial systems.

Design, develop, deliver, and support Java-based compliance and supervision technology for global markets. Build API-first, event-driven, microservices, and cloud-native solutions integrating vendor platforms, proprietary systems, and enterprise data services. Partner with Compliance, Risk, Data, Security, Architecture, and business stakeholders. Ensure solutions satisfy regulatory obligations through auditability, traceability, entitlement controls, monitoring, and evidencing. Participate in Agile delivery, continuous improvement, audits, regulatory reviews, and remediation programs.

Design, develop, modernize, test, deploy, and support full-stack enterprise applications using Java and modern frontend technologies. Own complex features end to end, troubleshoot performance and scalability issues, contribute to architecture and technical decisions, apply clean code and automated testing practices, and use AI tooling throughout the development lifecycle. Collaborate with product, QA, and UX teams, mentor junior engineers, document systems, and participate in Agile planning and process improvement.

Develop and deliver Java/Kotlin swap-processing components for Citi’s Strategic Swaps Platform. Responsibilities include test-driven development, automated testing, Agile delivery, CI/CD, technical analysis, system design, documentation, production support, and reliability improvements. The role also involves collaborating with management and technical leadership, resolving complex application issues, contributing to architecture and process enhancements, and coaching junior developers. Experience with cloud, messaging, databases, observability tools, and swaps or prime brokerage is advantageous.

Develop and maintain Java-based BDD test automation using Cucumber, SQL validation, and API testing. Create test plans, cases, estimates, regression suites, and project artifacts; identify and track defects; investigate production issues; and collaborate with development, business, and support teams. Help optimize QA processes, apply testing methodologies, and ensure software quality before client delivery.

Design, develop, and maintain low-latency electronic trading systems for equities execution. Build algorithmic trading, smart order routing, market data, exchange connectivity, monitoring, reconciliation, and recovery solutions. Collaborate with traders, quantitative researchers, product teams, infrastructure, support, and QA. Improve testing, performance, CI/CD, Agile delivery, and platform resiliency while contributing technical leadership in a globally distributed environment.

Develop and enhance Citi’s low-latency Global Equities Market Data platform. Responsibilities include designing new functionality, supporting deployed applications, coordinating exchange-mandated changes, troubleshooting production issues with traders and support teams, and improving electronic trading capabilities. The role requires strong Java or C++ expertise, network protocol knowledge, and teamwork in a fast-paced financial technology environment. Experience with microservices, ultra-low-latency systems, multicast networking, algorithmic trading, KDB, and equities products is beneficial.

Develop and support an endpoint security product using Java, Node.js, TypeScript, and React. Investigate enterprise customer issues, debug complex systems, analyze logs, profile performance, and identify root causes. Collaborate with global Support, QA, Product, and Engineering teams, contribute to product roadmap decisions, and develop security solutions within an agile environment.

Develop and maintain Elasticsearch’s Inference API and plugin framework, integrating internal and external AI providers. Responsibilities include API and protocol design, streaming, asynchronous execution, rate limiting, configuration, billing integration, error handling, open-source contribution reviews, incident response, and comprehensive unit, REST, and rolling-upgrade testing. The role requires advanced Java expertise, concurrency and parallelism knowledge, API design skills, cross-functional collaboration, and autonomous work in a distributed team.

Develop and maintain Java-based market access gateway systems connecting Citi’s trading infrastructure with EMEA exchanges. Responsibilities include application development, system enhancements, support and maintenance, vulnerability analysis, testing, debugging, troubleshooting, and stakeholder consultation. The role also provides technical guidance to junior analysts and requires independent problem-solving in a financial services environment. Desirable experience includes containerization, DevOps tools, Unix and shell scripting, and low-latency coding principles.

Develop and test cloud-based full-stack applications and prototypes using Java, Spring Boot, Python, TypeScript, Angular, and Azure. Build REST APIs, integrate microservices and event-driven systems, create accessible responsive interfaces, contribute to CI/CD and automated testing, and apply secure coding practices. Collaborate with architects, data engineers, and UX designers during discovery-phase projects. The role requires active SC clearance and occasional travel to London.

Design, implement and evolve core components of a Java-based distributed runtime: cluster services, distributed data structures and execution engines. Work on partitioning, replication, coordination and recovery, write reliable low-latency production code, contribute to architecture, reviews and mentoring.

Develop core infrastructure and horizontally scalable APIs for Elasticsearch. Resolve complex performance and concurrency issues, improve cloud operations and observability, automate developer workflows, and support operational investigations. Lead cross-team projects, collaborate with open-source communities, and own technical designs and implementations from inception through delivery. Apply strong Java expertise, CI/CD practices, AI-assisted development, and distributed-team communication.

Design, build, maintain, and debug services within a large-scale microservices architecture. Resolve complex distributed-system and production issues, participate in on-call rotations, communicate technical decisions, navigate ambiguity, and improve engineering practices through innovation, infrastructure migrations, technical-debt reduction, and AI-assisted development.

Lead a team developing and optimizing regulatory reporting systems and large-scale financial data pipelines. Responsibilities include hands-on Java and Spring Boot development, microservices and component design, Spark/Hadoop/Hive data processing, Kafka streaming, database optimization, automated testing, secure coding, regulatory onboarding, Agile execution, and technical communication with business, compliance, and technology stakeholders. The role also explores AI/ML automation and anomaly detection within reporting workflows.

Senior full‑stack engineer responsible for designing and delivering scalable, cloud‑native applications using Java or Python. Solve complex business problems, set coding standards, mentor mid‑level developers, integrate Gen‑AI capabilities (LLMs, prompt engineering, vector search) and third‑party Gen‑AI APIs, and collaborate with management to deploy new products while ensuring compliance and risk controls.

Design, build, test, and maintain Java 17+ microservices for a banking modernization program. Develop REST APIs and messaging integrations, containerize and deploy services through CI/CD, integrate relational and NoSQL databases, and address performance, resilience, security, and observability. Participate in Agile delivery, solution design, code reviews, testing, and production releases while collaborating with architects, analysts, testers, and product owners.

As a Senior Java Developer, you'll lead software development using Java and AWS, collaborating in an Agile team, adhering to best practices, and creating maintainable solutions.

The Staff Software Engineer will design and manage end-to-end data pipelines, ensuring data quality and governance while collaborating across Java and Python systems, including event schema design and AI tooling.

Design, build, and optimize low-latency, high-throughput Java microservices and REST APIs for payments. Deploy and scale services on OpenShift/Kubernetes and AWS, integrate with MongoDB/other datastores, improve performance and observability, mentor engineers, and drive architectural best practices.

Develop and enhance the Global Market Data low-latency platform for Equities: design microservices, implement new functionality, support production systems, coordinate exchange changes, and troubleshoot with traders and support teams.