Top Software Engineer Jobs in Belfast

Design, maintain, and scale backend services and APIs connecting Phantom Cash to blockchains. Build reliable event-driven systems with REST APIs, distributed-system patterns, retries, idempotency, and data consistency. Collaborate across teams, document decisions, mentor engineers, and improve engineering standards. The role also involves blockchain integrations, operational ownership, observability, and delivering dependable financial products in a remote crypto environment.

Freelance software developer responsible for designing, developing, testing, and maintaining high-performance applications. Collaborate with cross-functional teams to deliver innovative, client-focused solutions on a remote, on-demand platform.

Join ROOST's Coop project to design, implement, test, document, and release trust-and-safety features. Work across backend APIs, GraphQL, databases, and UI to improve reviewer workflows, detection integrations, and reporting. Lead code quality, security practices, community contribution reviews, and stakeholder coordination while engaging with users and the open source community.

Join the ROOST Osprey team to design, implement, test, and maintain a high-performance, real-time safety rules engine. Work includes building data/event pipelines, scaling and containerizing services, integrating with Kafka and gRPC, reviewing community contributions, maintaining code quality and security, and engaging with users and open source contributors to prioritize and deliver features.

Build a decentralized, serverless P2P search stack using Node.js. Implement and evaluate distributed indexing, DHTs, CRDTs, and networking (NAT traversal, encryption, multiplexing). Optimize protocols and high-concurrency networking code and work with the Holepunch stack components like hyperdht and hyperswarm.

Develop and maintain Microsoft Dynamics 365 and contact centre platform solutions, build API and middleware integrations, and apply CI/CD, automation, testing, and DevOps practices. Support production systems, troubleshoot performance, contribute to architecture and solution design, and drive continuous improvement. Mentor engineers and help maintain strong engineering standards across Westpac’s modernised contact centre platforms.

As a Software Engineer, you will build and maintain financial platforms and applications that help homeowners track and manage their expenses, collaborate with the engineering team, and utilize AI for data insights.

As a Backend Software Engineer, you'll develop and maintain REST APIs using Django, manage cloud infrastructure, and oversee CI/CD pipelines to support consumer fintech applications.

As a Software Engineering Intern, you will contribute to building features for user-facing products, APIs, and scalable services for machine learning. Responsibilities include crafting code, designing data pipelines, implementing tools, and enhancing technical documentation.

Lead technical teams to design, build, test, and maintain modern, scalable, secure software. Provide technical ownership for product architecture, estimation, planning and requirements. Coach and develop junior staff, drive CI/CD practices, troubleshoot live applications, and liaise with customers as the teams technical leader.

Build and operate stateful streaming pipelines and Go services that process usage events into accurate, near-real-time billing data. Responsibilities include ingestion, validation, enrichment, pricing, storage integration, usage APIs, billing exports, failure recovery, idempotency, exactly-once processing, reconciliation, scalability, observability, and deployment ownership.

Design and build distributed backend services for the cloud monetization platform, focusing on correctness, consistency, scalable microservices, distributed transactions, and reliable asynchronous workflows. Influence system architecture, own service implementations, and collaborate across teams to support billing, reservations, payments, and revenue flows.

Build and maintain integrations for North's agentic platform, own the end-to-end integration pipeline, create evals and tests to ensure reliability, tune tool descriptions, and help other engineers add and maintain integrations while using AI responsibly to improve performance and quality.

Work as an embedded QA engineer for Unity Studio performing manual and exploratory testing, owning QA processes from requirements to sign-off, writing and maintaining test cases, managing defect lifecycles, collaborating with engineers/product managers, participating in agile ceremonies, and contributing to quality process improvements.

The Software Engineer will design, develop, and support the MEMX Trading system software, focusing on production support during US evening hours.

Build and maintain internal and public-facing APIs and services powering the Web App and developer experience. Develop API functionality, Admin API systems, WebSocket and REST behavior, and usage and billing integrations with Stripe. Investigate production issues and security vulnerabilities, write and review tested code, make technical decisions, and collaborate across engineering, Product, and Design teams.

Build and evolve Elastic’s MCP server, agent skills platform, developer tooling, CLI enhancements, and third-party AI ecosystem integrations. Develop and support libraries and integrations primarily in Go, with Rust and other languages. Establish evaluation-based correctness standards, collaborate with product teams and external partners, contribute product thinking, and improve developer experience across a globally distributed team.

We are seeking a collaborative Backend Engineer with Java expertise to design, build, and maintain backend services, focusing on operational excellence and system reliability. Responsibilities include architecture, automation, and supporting production environments in a multi-cloud setting.

Design, implement, and maintain scalable backend systems supporting Alpaca’s financial ledger and brokerage infrastructure. Own high-visibility features from design through deployment, collaborate with finance, operations, product, and engineering stakeholders, and improve system health. Build performant, reliable, maintainable services using modern distributed systems technologies while ensuring the ledger remains a correct source of truth for account transactions, reporting, and compliance.

Designs, develops, integrates, tests, and maintains production embedded Linux software for vehicle systems. Responsibilities include modern C/C++ and Qt/QML development, Yocto platform maintenance, Python automation, CI/CD, automated testing, debugging across hardware and software boundaries, release management, architecture, documentation, and production support. The role also provides technical leadership and mentorship while collaborating with multidisciplinary engineering, manufacturing, cybersecurity, and supplier teams.

Architects and develops enterprise Change Data Capture and data integration software across mainframe and distributed platforms. Processes transaction logs, analyzes database internals and binary formats, reverse engineers legacy systems, and resolves performance, reliability, compatibility, and data-integrity issues. Provides technical leadership, mentors engineers, collaborates on customer escalations, and supports critical production incidents and releases.

Lead technical strategy and architecture for personalization, search, and recommendation systems. Deliver scalable ML-powered features, mentor senior engineers, and improve engineering quality across cross-functional teams.

As a Principal Engineer at M&S, you'll drive technical strategy, influence architecture, and mentor engineers while delivering on personalization, search, and machine learning features in collaboration with cross-functional teams.

The Senior Software Engineer will lead the development of backend systems for payment processing, collaborating with teams, setting goals, and fostering quality and ownership in code development.

Lead design and implementation of scalable AI-centric systems for offensive security, develop agentic AI capabilities (LLMs, RAG), own feature lifecycle to production, mentor engineers, run design reviews, and integrate AI into microservice architectures with cloud, container, and messaging technologies.