Top Software Engineer Jobs in Belfast

Build and architect Base360.ai: design and launch booking, pricing, payments, operations, and AI-powered automation. Integrate platforms (Airbnb, Stripe, Twilio, OpenAI), scale systems internationally, and embed AI workflows to automate operations and optimize revenue.

The Software Engineer will design, develop, and maintain backend services and APIs for Speechify, ensuring they meet business and scalability requirements. The role involves collaboration on B2B solutions and aligning backend architecture with product strategy.

Develop and maintain scalable backend services and integrations using Java and Spring Boot. Design and consume REST APIs, work with PostgreSQL and Flyway, build event-driven solutions on AWS, containerise with Docker/Kubernetes, write automated tests, monitor with Datadog, and support production systems while collaborating across product and platform teams.

Design, build, and maintain cloud-native backend services and APIs using .NET/C#. Work on AWS serverless architectures, NoSQL data models, CI/CD pipelines, and cloud infrastructure. Collaborate with cross-functional teams, participate in design and code reviews, troubleshoot application and infrastructure issues, and ensure performance, reliability, and test coverage.

Full-stack software engineer (mid-level) focused on frontend using React and TypeScript, building backend services with Node.js/Express, working with PostgreSQL, and developing cloud-native/serverless features on AWS (Lambda, S3). Collaborate with product, design, and AI specialists to deliver secure, scalable, production-ready applications and improve performance, monitoring, and reliability.

Design, develop and integrate bespoke production test equipment and software for Sensata manufacturing lines; develop/debug test applications, optimize ATE performance, integrate with MIS traceability, liaise with suppliers and product design teams, and provide training and documentation to remote sites.

As a Software Engineer Intern, you'll develop innovative solutions, gain exposure to the software development lifecycle, and collaborate in an Agile environment at Visa.

Citi seeks a Senior Software Engineer (Java) to design and develop complex, high-performance systems for fixed income trade processing, utilizing Java and Spring technologies.

Design, prototype, and maintain high-performance systems software with emphasis on firmware, device drivers, hardware interfaces, and real-time communication (WebRTC/WebSockets/REST). Debug and resolve low-level issues, collaborate with cross-functional teams, participate in code reviews, ensure security and compliance, and contribute to continuous improvement and POCs.

Join the Middleware team to build and maintain microservices powering real-time message delivery, tenant lifecycle management, and search. Develop features, scale services, implement automation with GitOps/CI-CD, and collaborate with SRE and senior engineers on code reviews, documentation, and operational tooling.

The role involves writing high-quality back-end code in Java or Kotlin, contributing to architectural decisions, and automating SDLC processes. You will lead a small team, apply AI in projects, and ensure clear communication across distributed teams.

Build and maintain Samsara's Cloud Governance Platform across AWS and GCP, focusing on cloud IAM guardrails, automated compliance controls, and software supply-chain security. Implement SAST/DAST and secure CI/CD patterns, design scalable, reliable systems, translate regulatory requirements into automated controls, collaborate cross-functionally, and own components end-to-end while mentoring teammates and shaping the roadmap.

The role involves developing software solutions for credit risk management, applying cloud principles, and enhancing business processes while ensuring compliance standards.

Develop and optimize incident response capabilities, review logging setups, benchmark cloud performance, manage security configurations, and implement infrastructure as code with Terraform and Cloudformation. Collaborate with product teams to support IAM needs.

The Backend Software Engineer will manage the lifecycle of short-term projects, perform reliability analysis on applications, and interface with teams to deliver features.

As a Software Engineer on the Menu team, you'll develop and manage systems for accessing menu records, collaborate with Product, and own tasks while ensuring high-quality software delivery.

Design, maintain, and extend abuse detection and prevention systems for GitLab's SaaS platform. Serve as a core maintainer of a Ruby on Rails monolith, build anomaly detection and agentic AI mitigations, automate abuse response, collaborate with peer engineering and security teams, and produce runbooks and operational documentation.

The Senior Software Engineer II will enhance operational excellence by designing automated reliability systems, incident management tooling, and observability infrastructure while mentoring teams and implementing AI-driven solutions.

As a Senior Software Engineer, you will enhance the REDAPL platform, leading initiatives in data ingestion, processing, and supporting infrastructure-related projects while mentoring other engineers.

Lead design and delivery of scalable, cloud-native platform capabilities for Walmart US Payroll. Own full SDLC, integrate AI/ML components, run design reviews, mentor engineers, drive CI/CD, observability, and cross-team collaboration to ensure resilient, maintainable systems aligned with business goals.

Build internal AI enablement tools, workflows, and guardrails to help engineers use coding agents safely and productively. Evaluate models and agents, partner with teams to apply AI, track adoption and impact, and provide documentation, training, and advocacy across the engineering organization.

Design, build, test, deploy, and support backend services (primarily in Go) and contribute to TypeScript frontends. Own full feature lifecycle, lead delivery, drive architecture and code quality, participate in reviews, mentor juniors, handle production support and on-call duties, and improve tooling and observability.

Design, build, test and support secure, maintainable full‑stack features for DMPonline using Ruby on Rails, JavaScript, HTML/CSS. Contribute to backend services, databases/SQL, APIs, integrations, authentication/authorization, exports, and reporting. Use Git workflows, automated testing, CI/CD, Docker, Linux and Nginx. Investigate and resolve defects, incidents and performance issues, participate in code reviews, documentation and cross‑team collaboration with product owners, testers and researchers.

The Senior Back-End Software Engineer designs, develops, and maintains scalable backend systems while taking ownership of the software development lifecycle.

Lead Mark43's AI-enabled engineering initiative by designing and orchestrating multi-agent systems that plan, write, review, test, and deploy software. Write prompts, scaffolding, and tool integrations (VCS, test runners, internal APIs), evaluate agent performance, prototype LLM-based workflows, collaborate cross-functionally, mentor teammates, and contribute to on-call rotations.