Top Software Engineer Jobs in London

Design, develop, and maintain scalable backend systems for fintech products. Build REST APIs and microservices, improve existing systems, and support payments, treasury management, transaction booking, and crypto liquidity platforms. Use Java, PostgreSQL, and Spring Boot with clean code, TDD, DDD, and CI/CD practices. Collaborate with a high-performing team to deliver secure, maintainable products in a rapidly growing environment.

Design, develop, and maintain scalable backend systems for fintech products. Build REST APIs and microservices supporting card payments, treasury management, transaction booking, and crypto liquidity. Develop greenfield and existing systems using Java, Spring Boot, and PostgreSQL, while applying clean code, test-driven development, domain-driven design, and continuous integration and delivery.

Design, implement, test, and ship Firefox security and hardening features for enterprise users. Improve browser security architecture across operating systems, including privilege isolation, trust boundaries, cryptographic protocols, WebPKI, and security-sensitive web APIs. Investigate security issues, deliver maintainable fixes, and resolve stability, correctness, performance, memory, and multithreading challenges in a complex native codebase.

The Senior Software Engineer will enhance the core product by developing features and tools for Chainguard Images, collaborating with teams and ensuring product quality.

Own and design high-impact components of Chainguard's container image platform. Build and improve image build systems, tooling, and services at scale. Drive technical direction, participate in roadmap planning, collaborate cross-functionally, and mentor engineers to raise engineering quality.

Build innovative software products in the Special Projects Division addressing public health, agriculture, education, and aid-related challenges in Sub-Saharan Africa. Responsibilities include designing software architectures, developing on UNIX-based platforms, participating in code reviews, using disciplined version control, collaborating with teams, and potentially applying Django, React, Android, or PyTorch. The role may involve travel to Africa to understand local contexts.

Leads software engineering teams in designing, building, testing, and maintaining scalable, secure applications. Owns technical architecture, estimation, product planning, requirements, and delivery while using AWS, Node.js, TypeScript, Terraform, and AWS CDK. Provides technical direction, customer engagement, mentoring, coaching, and performance management. Applies modern development practices such as XP, TDD, continuous integration, continuous delivery, and production troubleshooting.

Build and ship reliable backend features for a mortgage engineering team using Python and modern backend technologies. Own work end to end, including technical design, implementation, testing, deployment, and iteration. Collaborate across engineering, product, frontend, and external partners while contributing to architecture, APIs, data modeling, performance, security, reliability, and developer experience. The role emphasizes product thinking, ownership, clean code, thoughtful reviews, and growth toward senior-level contribution.

Lead full-stack development of the Equities market-making and trading platform. Design and implement front-end (React/WPF) and back-end (.NET/C#) systems, drive cloud migration and replatforming, automate CI/CD and testing, mentor and lead teams, act as Scrum Master when needed, and ensure regulatory and risk compliance.

Design, build, and evolve customer-facing backend services and public APIs supporting multiple Chainguard products. Own features end-to-end, create technical design documents, collaborate with Product and Experience teams, and contribute to a fast-paced, product-driven roadmap. Build reliable, observable cloud-native services and shared platform capabilities, including authentication and notifications.

The intern will work on developing high-performance research platforms, create tools for trading strategies, and collaborate with teams to innovate financial technology.

Develop and maintain internal build, test, and integration tooling for the ML software stack. Build release processes, assist dependency management, guide developers on build best practices, collaborate with QA and engineers to resolve integration issues, and contribute fixes to the ML software stack.

Build high-performance, production-ready trading and research platforms in small teams. Design systems architectures, develop platforms and web frameworks, apply distributed computing, ML and NLP techniques, and collaborate on complex technical problems.

Build and operate high-throughput backend services for financial crime detection across WorldRemit and Sendwave. Responsibilities include developing alerting, screening, risk-rating, and agentic AI investigation workflows; integrating third-party compliance platforms; improving observability, reliability, and auditability; collaborating with compliance teams; reviewing designs and code; and participating in on-call production support. The role requires strong Java and Spring expertise, event-driven systems experience, and familiarity with cloud and infrastructure tooling.

Design, develop, and maintain scalable, secure backend systems for fintech products. Build REST APIs and microservices supporting card payments, treasury management, transaction booking, and crypto liquidity. Work primarily with Java, PostgreSQL, and Spring Boot while applying clean code, TDD, DDD, and CI/CD practices. Collaborate with a high-performing team to deliver greenfield and existing-system improvements.

Build, extend, and operate systems that provision, monitor, and orchestrate private network interconnects at scale. Design, implement, test, and deploy software; collaborate with Product, Network, and Infrastructure teams; participate in on-call rotations and maintain production health. Work with systems-level languages and network technologies (BGP, routing, overlays) across distributed services.

The Senior Options Software Engineer will design, develop, and support a high-performance trading platform, collaborating with business leaders to create innovative software solutions and handle complex systems support for trading activities.

Develop and maintain PHP Laravel and JavaScript applications for web and cross-platform mobile clients. Responsibilities include writing tested code, refactoring legacy systems, optimizing database queries, participating in code reviews and sprint planning, documenting functionality, resolving production issues, and assisting with AWS deployments. The role also contributes to design patterns, coding standards, CI/CD practices, and ongoing product improvements.

Build and maintain automated testing infrastructure across UI, browser extensions, endpoint agents, and backend services. Design cross-platform test environments, expand load testing, investigate bugs, integrate tests into GitLab CI/CD pipelines, establish quality gates, improve test reliability, and track coverage. Collaborate with engineers to resolve defects and shape the QA roadmap across Windows, macOS, and Linux.

Design, build, test, and operate secure full-stack features using Java-based microservices and event-driven architectures. Contribute to system design, debugging, automation, CI/CD, and production stability. Collaborate on architecture reviews, share engineering best practices, and responsibly use enterprise AI-assisted development tools.

Design, develop, and maintain secure, high-quality production code and system architectures. Troubleshoot complex issues, analyze large datasets for improvements, ensure application resiliency and CI/CD practices, and contribute to engineering communities and inclusive team culture.

Design, build, test, release, and operate secure, resilient full-stack features for production services. Lead architecture and delivery, author and review Java-based code, troubleshoot cross-service production issues, implement automation and CI/CD, improve performance and stability, and mentor teammates while responsibly leveraging enterprise AI-assisted development tools.

Design and implement large-scale browser-based rendering infrastructure to execute and extract structured content from JS-heavy web apps. Improve rendering quality, performance, cost, and throughput at internet scale and productionize rendering research.

Build and operate a scalable evaluation framework for computer-use agents and AI models. Responsibilities include benchmark integration, orchestration, scheduling, observability, reproducible trials, distributed systems operation, API and external-service integrations, customer collaboration, and framework standards. The role requires production backend development in Python, Kubernetes and public-cloud experience, database and messaging knowledge, and end-to-end system ownership.

Lead technical direction and delivery of large-scale AI/ML platforms. Architect microservices and shared libraries, align ML, data science and DevOps, coach distributed engineers, define production readiness, and drive hiring and standards across software engineering.