Top Backend Jobs in Belfast

Build secure, reliable, and performant backend features for GitLab repository management using Ruby and GraphQL. Develop APIs, data models, business logic, tests, and policy-based functionality while improving performance, observability, caching, and resiliency. Collaborate asynchronously across product and engineering teams, participate in Tier 2 on-call, troubleshoot incidents, review AI-generated code, and contribute to branch protection, Codeowners, merge strategies, and AI-powered repository configuration.

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 and optimize high-performance Elixir/Phoenix backend systems with PostgreSQL at scale. Design efficient schemas, queries, indexes, batching strategies, migrations, and concurrency patterns. Diagnose database bottlenecks, support large document volumes, and improve reliability across cloud and self-hosted deployments. Contribute to AI-assisted engineering workflows, platform architecture, tooling, and customer success while collaborating with a remote-first team.

Design, build, operate, and maintain scalable alerting backend systems. Drive features end-to-end, contribute to open-source, participate in on-call rotations, mentor teammates, and collaborate remotely to improve reliability, performance, and alert evaluation at scale.

Design and build scalable Python backend systems for a real-time AI voice-agent platform. Responsibilities include architecting microservices, APIs, distributed systems, databases, message queues, event-driven workflows, EHR integrations, observability, and HIPAA-compliant infrastructure. The engineer will own backend features end to end, ensure reliability and low latency at scale, and collaborate through technical discussions and code reviews.

Build, deploy, and maintain backend solutions for websites, digital products, APIs, and integrations using primarily Python, Django, and Wagtail. Improve security, performance, reliability, and testing; troubleshoot live services; participate in code reviews and on-call support; collaborate with engineers, designers, client success teams, and clients; and contribute to technical planning, documentation, and delivery.

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 operate high-traffic backend services for Universal Wallet, supporting fiat and stablecoin deposits, withdrawals, balances, integrations, and settlement. Develop across Python and Kotlin/Java stacks, design APIs and event-driven systems, improve architecture and observability, review code, and participate in on-call production support. Collaborate asynchronously across teams, influence technical decisions, and deliver reliable financial infrastructure.

Build and operate high-performance backend systems and distributed services using Elixir and Phoenix. Design declarative infrastructure with Terraform, Terramate, FluxCD, Kubernetes, and Helm; manage AWS cloud workloads, cluster upgrades, GitOps workflows, observability, and databases. Collaborate with a remote engineering team on architecture, product development, debugging, reliability, and customer success.

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.

Design, develop, test, and maintain scalable backend applications and integrations while replacing a critical legacy system. Troubleshoot technical issues, improve system resilience, support releases and deployments, and implement automated testing and continuous integration. The role requires expertise in Java, Spring Boot, Kafka, IBM MQ, DevOps practices, database design, and strong technical leadership and communication skills.

Leads backend architecture and streaming services for high-volume maritime tracking and trade data. Builds Python and PHP microservices, Kafka pipelines, and PostgreSQL and ClickHouse data systems. Owns production reliability, observability, CI/CD, and containerized deployments while collaborating with product, platform, and client-facing teams. Mentors engineers, drives modernization, and establishes technical standards.

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.

Build and secure backend systems that execute untrusted user code at scale. Responsibilities include designing sandboxed runtimes, threat detection, incident response, vulnerability management, penetration testing, security reviews, vulnerability disclosure, SOC 2 maintenance, and promoting security practices across engineering. The role requires backend engineering, offensive-security curiosity, runtime isolation experience, on-call participation, and collaboration with an open-source developer tools community.

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.