Top Backend Developer Jobs in London

Lead the technical direction and hands-on development of Push, a regulated non-custodial financial product. Design resilient backend services for payment initiation, transaction tracking, settlement, exceptions, notifications, partner integrations, blockchain execution, and customer wallets. Establish secure architecture, testing, observability, incident response, deployment, and on-call standards while leading engineers through complex, high-impact work and partnering with product, compliance, legal, security, operations, and finance teams.

Design and scale backend services, REST APIs, microservices, data pipelines, database schemas, caching layers, and event-driven systems for AI-powered media workflows. Integrate machine learning models into production, optimize performance and reliability, implement observability, resolve incidents, and collaborate with ML, DevOps, frontend, and product teams.

Lead development projects focusing on customer experiences and operational management. Mentor other engineers, make strategic tech decisions, and solve complex challenges while contributing high-quality code.

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.

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 maintain secure, scalable Flow Registry features for GitLab’s agentic platform using Python, LangChain, and LangGraph. Design GraphQL and REST APIs, improve automated testing, optimize PostgreSQL-backed applications, and collaborate across backend, frontend, product, UX, and AI teams. Participate in Tier 2 on-call support, troubleshoot production issues, improve observability, and contribute to responsible AI integration in GitLab’s remote, asynchronous environment.

Build and maintain the Payin Platform that handles how money enters Wise. Design Payin Session and Payment abstractions, ensure reliability and scalability for high-volume transactions, collaborate across teams, write testable code, drive end-to-end ownership, and improve APIs and systems for excellent customer experience.

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.

Own significant product areas from customer problem discovery through delivery, measurement, and iteration. Build AI-powered prototypes and production products, use AI coding tools daily, and engage directly with customers and commercial stakeholders. Lead small squads, influence product direction, communicate across technical and business teams, and contribute to an AI-native product engineering culture. The role is fully remote in the UK and focuses on EV energy, virtual power plants, and grid services.

Design and build scalable backend systems and microservices using Go. Lead testing, security, code quality, and continuous delivery practices; collaborate with clients, present technical solutions, mentor colleagues, and balance delivery speed with long-term system maintainability and performance.

Build and maintain backend AI capabilities for GitLab Duo Chat: design flow components and agentic flows in Python/LangGraph, integrate LLMs and multi-agent orchestration, implement and maintain APIs in the Rails monolith, improve observability and reliability, and participate in on-call rotations and cross-functional collaboration to deliver safe, scalable AI chat features.

Design, build, and maintain Aalyria’s cloud-native Spacetime platform for 5G non-terrestrial networks and Direct-to-Cell services. Develop distributed backend systems using C++, Golang, Java, gRPC, Protocol Buffers, and Kubernetes. Translate 3GPP and O-RAN specifications into tested software, build orchestration and federation APIs, integrate platform components, document implementations, and troubleshoot production issues.

Lead backend work for GitLab's Spec-Driven Development: design and build APIs, data models, evaluation systems, and agent-driven workflows using Ruby on Rails and Python. Ship production services, benchmark LLM workflows, coordinate multi-person projects, mentor engineers, and collaborate with product and design in an all-remote, async environment.

Design, develop, test, and maintain scalable backend services and APIs for Agent Studio. Build orchestration, configuration, integrations, deployment, lifecycle, authentication, authorization, observability, and runtime management capabilities. Collaborate with frontend, AI/ML, product, UX, DevOps, and platform teams to deliver reliable, secure, high-performance services. Troubleshoot complex production issues and contribute to technical designs, code reviews, testing, and continuous engineering improvements.

Designs, develops, and maintains scalable backend services, APIs, and data capabilities for analytics, dashboards, and visualizations. Responsibilities include processing and aggregating structured and unstructured data, optimizing performance, collaborating with frontend, data, UX, product, and DevOps teams, and supporting reliable production deployments. The role also involves technical design, testing, monitoring, troubleshooting, code reviews, and continuous improvement of analytics services.

As a Principal Backend Engineer, you will build scalable backend services with Java, design APIs, implement microservices, and work with AWS cloud technologies.

Lead and manage a cross-functional engineering team to design, build, and operate a high-scale payments app. Drive architecture, delivery, code quality, reliability, observability, and incident response while coaching engineers and improving processes to ship customer-focused products quickly and reliably.

Lead and manage a cross-functional engineering team to deliver reliable, scalable customer-facing products. Drive architecture, code quality, testing, observability, incident response, and engineering processes. Coach and develop engineers, prioritize work with product and design, and ensure fast, high-quality delivery from idea through production.

Lead and grow a high-performing engineering team building scalable, customer-facing products. Own engineering delivery, architecture, code quality, observability, incident response, and engineering culture. Partner with product, design, mobile, backend and AI teams to turn ambiguous problems into production systems while coaching engineers and improving processes to deliver reliable, high-quality outcomes.

Lead technical design and execution of products for an AI-enabled payments app. Hands-on coding, architecture, system design, code review, debugging, production ownership, mentoring engineers, improving dev tooling, and collaborating with product, design and AI teams to ship reliable, scalable systems.

Lead and manage a cross-functional engineering team to design, build, and operate customer-facing products. Own technical architecture, delivery, code quality, reliability, observability, and incident resolution while coaching engineers and improving processes to scale product and engineering outcomes.

Lead and manage a cross-functional engineering team to design, build, and operate scalable, reliable production systems. Own technical architecture, delivery, code quality, observability, incident response, and engineering processes while coaching engineers and driving product outcomes in partnership with product, design, mobile, backend and AI teams.

Own high-impact backend challenges across services and teams, shape architecture, improve performance, resilience, data integrity, observability, and failure handling. Lead technical decisions, resolve systemic problems, mentor engineers, raise review quality, and partner with product and engineering leadership on long-term technical investments. The role remains hands-on and emphasizes distributed systems, relational databases, concurrency, asynchronous communication, and reliable operation at scale.

Own backend services end to end, from requirements and system design through development, testing, deployment, and production operations. Design scalable, resilient, high-performance systems with strong data integrity, diagnose complex production issues, and make sound technical trade-offs. Collaborate with product and engineering teams, review code, share knowledge, and improve engineering standards. The role requires backend microservices experience, protocol expertise, modern framework fluency, deep relational database knowledge, and experience building highly available systems.

Lead the design, development, and optimization of scalable backend services in Python and Rust. Architect distributed systems, improve reliability through monitoring and alerting, enforce testing and CI/CD best practices, and contribute to backend architecture decisions. Collaborate with product and engineering teams on complex projects, mentor engineers, and ensure the performance and stability of critical platform services.