Top Software Engineer Jobs in London

As a Fullstack Software Engineer, design and optimize performance-critical systems, manage backend services using C#, and collaborate with frontend teams to enhance product features.

Design, build, and operate scalable, fault-tolerant connectors between Fonoa and enterprise systems (ERPs, billing platforms). Own integrations end-to-end, work closely with product and customers, handle retries/idempotency/data consistency, record operational datasets, and use insights to improve products.

The Senior Back-End Software Engineer will implement features, improve logic, write integrations with APIs, and contribute to design discussions within a startup environment.

Design, build and operate cloud-native .NET microservices on Azure. Deliver features with test-first practices, define CI/CD and IaC, ensure scalability, reliability and support SRE-driven operations.

The Software Engineer Consultant will design and deliver secure software for UK Defence, collaborating with stakeholders and applying secure development practices.

Develop and maintain security-focused cloud services and infrastructure, design APIs and backend systems, integrate with embedded platforms, fix bugs, write automated tests, and apply cloud and secure software best practices to ensure scalable, reliable, and secure operation.

Back-end engineer to build and scale NLPatent's AI-first patent research platform. Work with CTO and senior engineers to develop Python/Django services, containerized deployments, and relational database-backed features. Collaborate on integrating NLP/LLM capabilities and ensure production-ready systems. Hybrid role requiring three days onsite weekly.

Join a fast-growing AI-based company as a software engineer to develop and scale their platform while impacting product strategy and architecture.

Seeking a full-stack software engineer to contribute to product growth and scaling operations. Role requires development in Typescript and AWS on a collaborative team.

Design and build scalable microservices, APIs, and data pipelines for high-dimensional simulation data. Implement data storage and ingestion for ML workloads, enable BI and visualization tools, own features end-to-end, maintain CI/CD and observability, and collaborate with data scientists to ensure secure, reliable, performant systems.

Work with customers and cross-functional teams to turn AI-driven simulation research into reusable engineering applications. Build and maintain frontend interfaces and backend services, design APIs, write clean, tested code, optimise performance, and contribute to architecture and CI/CD. Translate customer workflows into product capabilities and mentor junior engineers.

Lead architecture and full-stack development of AI-powered platforms, build scalable frontend and backend systems, mentor engineers, translate client problems into production-ready solutions, and ensure high code quality and reliable deployments.

Design, build and scale full-stack AI-powered systems. Own frontend and backend architectures, lead cross-functional teams, mentor junior engineers, provide technical authority, and collaborate with clients on architecture and deployment.

The Senior Full Stack Engineer will design, develop, and maintain scalable features, improving user experience and collaborating with teams on software solutions.

The role requires training large language models to improve code quality, involving code review, ranking, and feedback integration for reinforcement learning.

As a Software Engineer, you'll train large language models to write quality code, review code snippets for performance and correctness, and provide feedback for ongoing improvements in a remote, independent contractor role.

The engineer will train large language models to write code, review and refactor AI-generated code, and inject feedback into a reinforcement learning pipeline.

The role involves training large language models to improve code quality by reviewing and refactoring AI-generated code, providing feedback to enhance the learning process.

Develop robust .NET backend applications and APIs, integrating with SQL Server and external APIs, while optimizing data access and workflows.

The Software Engineer will design, build, and maintain robust applications and data infrastructure, collaborate with multiple teams, and improve data quality.

As a Software Engineer, you'll design and maintain APIs, solve technical challenges, and guide team members while optimizing performance metrics.

The role involves automating testing for Connected TV applications, maintaining CI pipelines, mentoring juniors, and designing frameworks while collaborating closely with a quality engineering team.

As a Senior Software Engineer, you'll lead backend development, improve SDLC processes, and mentor engineers, primarily using Java and Kotlin.

The role involves developing and maintaining enterprise software across the stack, ensuring scalability and reliability, and embedding DevOps practices while mentoring junior developers.

As a Senior Developer, you will enhance finance platforms using C# .NET and AI tools, ensuring compliance and high-quality software delivery.