Top Backend Jobs in Belfast

Lead the technical direction and architecture of the Foundations platform team, owning authentication, authorization, SSO, secrets management, tenancy, and core platform services. Design APIs, drive services through launch, make technical decisions, establish engineering standards, and mentor engineers without formal management authority. Partner with engineering and product leaders to align execution with priorities.

Senior backend engineer responsible for designing, coding, and operating highly available distributed identity systems for Affirm’s international markets. The role includes owning quarterly goals, delivering scalable features in Kotlin and Python, collaborating across product and engineering teams, improving code and design standards, monitoring system availability, resolving production issues, mentoring engineers, and supporting technical planning and hiring.

Build backend data frameworks and tooling that keep GitLab’s datastores scalable, healthy, and safe across SaaS and self-managed deployments. Develop retention and lifecycle controls, schema-change guardrails, bulk data removal tools, SQL traffic replay, and background operations frameworks. Collaborate across engineering and product teams, review database changes, improve performance and migration safety, document best practices, and participate in a tier 2 database on-call rotation.

Build, test, ship, and operate production backend features using Ruby/Rails, Go, or other modern languages. Design APIs, background jobs, integrations, data models, migrations, and services while ensuring security, performance, reliability, and observability. Review code, investigate failures, reduce technical debt, provide operational support, collaborate asynchronously with product and engineering teams, and use AI coding tools responsibly.

Provides technical leadership across teams by designing and delivering large-scale backend initiatives, modernizing monolithic systems, defining architecture and engineering standards, and improving reliability, security, observability, and operability. The role establishes Go and Kubernetes patterns, guides Rust adoption, participates in incident response, mentors engineers, influences platform roadmaps, and leads safe adoption of AI-assisted and agentic engineering workflows.

Design, build, and maintain secure, tested, performant backend integrations connecting GitLab agents with tools such as Slack, Claude Code, and Codex. Own complex features, develop GraphQL and REST APIs, improve automated testing, troubleshoot production issues through on-call rotations, enhance observability and resiliency, and collaborate across product, frontend, backend, and AI engineering teams.

Set long-term technical strategy for backend identity systems, lead major distributed-system initiatives, ensure operational availability, establish engineering quality standards, collaborate cross-functionally, and mentor engineers. Build and launch highly available systems supporting international expansion, KYC verification, identity data management, decisioning, regulatory compliance, and global risk models.

Build and scale event-driven microservices for M-KOPA Mobility using C#/.NET. Own solutions throughout their lifecycle, from architecture and development through deployment, observability, monitoring, and decommissioning. Work with Azure, messaging systems, Kubernetes, Docker, automated testing, infrastructure as code, and DevOps practices while collaborating with distributed teams and coaching other engineers.

Lead the design, development, testing, and maintenance of scalable backend software applications. Provide technical leadership through mentoring, code reviews, architectural decisions, and best-practice adoption. Collaborate with product, design, and stakeholders to define requirements, manage technical risks, and deliver secure, reliable solutions. Champion continuous integration, code quality, automated testing, data protection, and compliance while driving innovation and fostering a high-performing engineering culture.

Lead cross-functional Developer Experience initiatives across six teams, contributing hands-on backend code in Ruby and Go. Improve testing reliability, test coverage, CI/CD pipelines, logging standards, and development environments. Partner with engineering, platform, product, and infrastructure teams to identify friction, remove systemic bottlenecks, shape the Developer Experience Platform strategy, and foster continuous engineering improvement.

Design, develop, test, and maintain scalable backend, frontend, API, and integration solutions. Troubleshoot technical issues, support system stability, and contribute to deployments and release processes. Ensure strong API design, security, performance, coding standards, automated testing, and continuous integration. Collaborate with cross-functional teams, document SDLC activities, mentor developers, analyze recurring issues, and lead continuous improvement initiatives.

Build and operate core components of a distributed, multi-tenant database and SaaS data platform, including ingestion, query planning, distributed execution, storage formats, APIs, tenant isolation, quotas, audit logs, and background jobs. Develop agent-facing retrieval interfaces, instrument services with observability tooling, and shape architecture as the product evolves from prototype to production. Collaborate across product and infrastructure while making pragmatic decisions in an autonomous environment.

Own technical direction and execution for major products and systems. Design scalable backend, frontend, API, database, and infrastructure solutions; write code; prototype; review code; debug production issues; make architecture trade-offs; convert ambiguous problems into execution plans; improve engineering quality; lead critical initiatives; and mentor engineers.

Build and own backend services, APIs, workflows, and financial infrastructure for an AI neobank. Responsibilities include supporting onboarding, payments, accounts, cards, transfers, rewards, travel, FX, KYC, and risk flows; integrating with financial partners and third-party platforms; and ensuring reliability, security, scalability, observability, and data integrity. The role collaborates with product, frontend, mobile, and AI teams to deliver production systems for millions of users.

Develop and maintain Tailscale’s control plane, relay infrastructure, identity integrations, open-source client code, and backend services. Design, test, document, and operate scalable software, emphasizing observability, security, incident response, customer escalations, and system stability. Collaborate asynchronously with engineers, product managers, and designers while contributing to product strategy and the full product lifecycle.

Leads technical direction and hands-on execution for major products and systems. Designs scalable backend, frontend, API, database, and infrastructure solutions; writes code; drives architecture decisions; solves production issues; improves engineering quality, reliability, security, testing, and observability; and mentors engineers across teams.

Own technical direction and execution for major products and systems. Design scalable and reliable architectures, write production code, lead architecture decisions, solve complex engineering problems, and drive initiatives from concept through production. Improve engineering quality across testing, security, observability, and development practices while mentoring engineers and coordinating work across teams and products.

As a Senior Backend Engineer at DuckDuckGo, you'll lead backend projects, mentor engineers, and develop AI-enhanced features for the company's privacy-centric product line.

Design, develop, test, and maintain scalable backend applications, services, and APIs using modern engineering practices. Responsibilities include architecture and solution design, unit and integration testing, troubleshooting, code reviews, technical discussions, Agile collaboration, continuous improvement, and mentoring junior engineers. The role emphasizes performance, reliability, scalability, security, maintainability, and translating business requirements into high-quality technical solutions.

Develop backend blockchain functionality for Cardax DEX on the Cardano blockchain. Write and maintain smart contracts in Plutarch and Haskell that define the constraints and conditions for decentralized token exchange without a central entity.

Build and operate backend services for an AI-native context management system, including ingestion, indexing, retrieval APIs, multi-tenant SaaS infrastructure, agent integrations, and administration tools. Define architecture, storage, service boundaries, and API contracts while instrumenting systems for reliability. Work autonomously in an early-stage environment, iterate rapidly, collaborate across teams, and deliver scalable production software for AI-agent workflows.

Build and operate GitLab’s Gitaly backend storage systems, focusing on distributed storage, Git repository management, reliability, scalability, performance, and observability. Own complex technical initiatives end to end, lead system design, collaborate across engineering and customer-facing teams, mentor engineers, improve development practices, respond to incidents, participate in on-call duties, and implement operational improvements for production systems.

Build and own scalable backend microservices for call treatment orchestration, brand data, analytics, and billing. Design event-driven and hexagonal architecture solutions using Java and Spring Boot, relational databases, caching, and event-streaming platforms. Contribute to technical decisions, production support, reliability improvements, troubleshooting, and distributed team collaboration.

Build and operate high-traffic Java backend services for identity, authentication, onboarding, KYC, login, and account recovery. Design REST and gRPC APIs, event-driven systems, and database-backed services while improving architecture, monitoring, reliability, and tooling. Participate in code reviews, production support, on-call rotations, incident remediation, and cross-functional collaboration. Contribute to frontend user experience and apply AI tools responsibly in a regulated fintech environment.

Design and build backend platform and SDK features for an open-source and cloud product. Responsibilities include database schema design, query optimization, scalable APIs, reliable production systems, security, observability, architecture, and technical roadmap development. The role also involves customer support, code reviews, documentation, open-source participation, and occasional on-call work.