Top Java Developer Jobs in Belfast

Lead the design, development, architecture, deployment, and support of scalable full-stack financial applications for a trade-processing platform. Responsibilities include Java and Spring Boot development, REST APIs, microservices, technical documentation, test-driven development, incident management, root-cause analysis, and regulatory and security compliance. The role may also involve React or Angular frontend development and responsible use of AI tools.

Lead development of enterprise Java applications, microservices, REST services, and event-driven systems using Kafka. Design scalable solutions, optimize SQL, implement testing and CI/CD practices, maintain code quality, and solve complex technical problems. Mentor and manage application developers while collaborating with technology and product teams on cloud-native systems and container orchestration.

Develop and maintain Java-based microservices using Spring Boot, RESTful services, SQL, and enterprise software engineering practices. Build scalable solutions, optimize queries, contribute to CI/CD pipelines, manage source code, uphold code quality, and implement comprehensive testing. Collaborate with application developers to solve complex technical problems and deliver reliable corporate action event platforms.

Lead architecture and hands-on development of Java and Spring Boot microservices for enterprise vendor and market data systems. Design data models, ingestion and reconciliation pipelines, REST APIs, and cloud-native deployments. Provide technical leadership, mentorship, architectural governance, and end-to-end integration oversight while promoting AI-assisted development tools and modern engineering practices.

Design and maintain Java and Spring Boot microservices, REST APIs, high-throughput ingestion and reconciliation pipelines, relational data models, SQL queries, audit logs, and automated tests. Collaborate on React and TypeScript features, CI/CD, Docker/OpenShift deployments, and enterprise integrations. Use AI-assisted development tools, contribute to architectural decisions, mentor junior engineers, and work with distributed global teams.

Build and maintain Java/Scala ETL systems supporting financial regulatory reporting across global jurisdictions. Collaborate with business analysts and QA teams to translate requirements into strategic technology solutions. Responsibilities include architecture, design, code reviews, production support, application maintenance, regulatory and audit compliance, data security, and issue resolution. The role also involves supporting complex financial calculations and ensuring accurate, secure reporting data delivery.

Lead architecture and hands-on development of Java and Spring Boot microservices for enterprise vendor and market data ingestion, reconciliation, and REST API platforms. Design relational data models, transactional pipelines, APIs, and cloud-native deployments while mentoring engineers and shaping technical strategy. Collaborate with product and architecture teams, oversee full-stack integration with React and TypeScript interfaces, and promote AI-assisted development using tools such as Devin, GitHub Copilot, and Cursor.

Build and maintain high-throughput Java and Spring Boot microservices, REST APIs, data ingestion and reconciliation pipelines, relational data models, and transactional processing systems. Optimize SQL and enterprise integrations while applying TDD, CI/CD, containerization, and secure coding practices. Collaborate on React and TypeScript interfaces, use AI-assisted development tools, mentor engineers, and deliver features independently within a global agile team.

Develop and enhance Citi’s global equities market data platform using Java or C++. Build ultra-low-latency functionality, support production systems, coordinate exchange-driven changes, troubleshoot issues with traders and support teams, and improve electronic trading applications. The role requires strong network protocol knowledge, teamwork, communication, testing, code reviews, and agile development practices.

Develop scalable full-stack financial applications using Java or Python, backend frameworks, modern JavaScript, and cloud platforms. Design application architecture, coding and testing standards, and system enhancements. Integrate generative AI APIs and technologies such as LLMs, vector search, prompt engineering, and agent workflows. Analyze complex technical and business problems, manage risk and compliance, and mentor mid-level developers and analysts.

Design, develop, and maintain high-performance, low-latency electronic trading systems for equities execution. Collaborate with traders, quantitative researchers, product teams, infrastructure, support, and QA to deliver algorithmic trading, smart order routing, connectivity, market data, monitoring, reconciliation, and recovery capabilities. Improve testing frameworks, development tools, Agile practices, CI/CD, and platform reliability while contributing technical leadership in a globally distributed environment.

Lead a team developing and optimizing regulatory reporting frameworks and large-scale data pipelines. Design microservices and data integration components using Java and Spring Boot, process distributed datasets with Spark, Hadoop, and Hive, and build Kafka streaming solutions. Translate regulatory requirements into technical specifications, oversee testing and secure coding practices, mentor engineers, and support Agile delivery. Integrate AI and automation concepts for anomaly detection and data classification while optimizing MongoDB and relational database performance.

Develop and maintain Java-based market access gateways connecting Citi’s trading systems to EMEA exchanges. Translate internal trading messages, support application systems, troubleshoot issues, identify vulnerabilities, test and debug code, and implement enhancements. Collaborate with users and technology teams, provide application support, advise junior analysts, and operate independently while managing risk and compliance. The role also values Python, containerization, DevOps, Unix scripting, and low-latency coding experience.

Develop and deliver Java/Kotlin swap-processing components for Citi’s Strategic Swaps Platform. Responsibilities include test-driven development, automated testing, CI/CD, technical design, analysis, documentation, production support, reliability improvements, and collaboration across technology and business teams. The role also involves advising junior developers, contributing to Agile planning, resolving complex technical issues, and supporting continuous improvements to coding, testing, and deployment standards.

Develop and maintain Java-based BDD test automation using Cucumber, execute API and database testing with SQL, and create test plans, cases, estimates, and regression suites. Identify and track defects, serve as a quality gate, investigate production issues, collaborate with development and business teams, and improve scalable QA processes. The role supports financial applications within Citi’s Equity Finance transformation program.

Build and operate core components of Serverless Elasticsearch, focusing on distributed systems, cluster coordination, indexing, scalability, performance, and resilience. Investigate and resolve complex concurrency, stability, and operational issues across large-scale systems. Own projects end to end, collaborate across distributed teams, and support engineers with advanced technical problems.

Develop cloud-based Java microservices for Motorola Solutions’ CC Responder platform. Responsibilities include full software development lifecycle activities, integrating services with other software components, testing, documentation, and supporting existing customers. The role uses agile Scrum practices and technologies including Docker, Azure, Cosmos DB, and Azure Service Bus, with preferred experience in Spring Boot, Kubernetes, Python, and BDD testing.

Develop and maintain Java/J2EE microservices using Spring Boot, RESTful services, SQL, and modern software engineering practices. Build reliable applications, optimize queries, contribute to CI/CD pipelines, manage source code, enforce code quality, and implement comprehensive testing. Analyze complex technical problems and collaborate with application development teams in a financial services environment.

Leads the design, development, and deployment of enterprise Java applications, microservices, REST APIs, and event-driven systems using Kafka. Responsibilities include SQL optimization, CI/CD, source control, code quality, automated testing, cloud-native development, container orchestration, technical problem-solving, and mentoring application developers. The role also drives software engineering best practices, architecture, and continuous improvement across the team.

Lead the design, development, delivery, and operational support of Java-based compliance and supervision technology for global markets. Guide engineering teams, establish development and quality standards, oversee enterprise distributed systems, and deliver API-first, event-driven, microservices, and cloud-native solutions. Partner with compliance, risk, data, architecture, security, vendors, and business stakeholders to meet regulatory obligations, strengthen controls, and ensure scalable, secure, resilient, auditable systems.

Design, develop, deliver, and support Java-based compliance and communications surveillance technology for global markets. Build API-first, event-driven, microservices, and cloud-native solutions while integrating vendor platforms and enterprise data services. Ensure scalability, security, resiliency, auditability, and regulatory alignment. Collaborate with Compliance, Risk, Data, product, architecture, infrastructure, security, vendors, and business stakeholders using Agile and continuous delivery practices.

Principal Software Engineer responsible for designing, building, and operating distributed systems powering Serverless Elasticsearch. The role focuses on cluster coordination, concurrent and consistent indexing, scalability, resilience, performance, and operational stability across large-scale deployments. Responsibilities include resolving complex concurrency and performance issues, supporting engineering teams, leading projects across multiple engineers, and owning technical initiatives from design through delivery.

Develop core infrastructure and horizontally scalable APIs for Elasticsearch. Solve complex performance, concurrency, stability, and observability issues; improve developer productivity through automation and AI-enabled workflows; support cloud and serverless operations; and lead cross-team engineering projects from design through delivery.

Designs and maintains high-performance JVM applications for digital-asset trading and settlement. Responsibilities include developing microservices, REST APIs, WebSockets, SQL and NoSQL data schemas, Kafka messaging, Redis caching, and cloud-native AWS solutions. The engineer collaborates with business stakeholders, DevOps, and frontend teams; supports GitLab CI/CD; and implements observability, structured logging, scalability, availability, and data integrity across a regulated financial platform.

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.