11 developer jobs found in London

Role: Senior C# Developer Location: London (Remote) Day Rate: Up To £600 Per Day Type: Contract (Outside ir35) A highly regarded financial institution is seeking an experienced C# Developer to join their technology team on a contract basis. This role sits within a fast-paced environment focused on delivering robust, scalable solutions that support critical business operations. Key Responsibilities Develop and maintain high-performance applications using modern Microsoft technologies Collaborate with cross-functional teams to define, design, and deliver solutions Contribute to architectural decisions and best practices Ensure code quality, performance, and reliability through testing and optimisation What We're Looking For Extensive experience in software development using C# and the .NET ecosystem Strong understanding of modern application architecture and design principles Proven ability to build scalable and maintainable systems...

JWT / JSON Developer Location: London - Hybrid / 2 days per week onsite Contract Length: 6 months Day Rate: Up to £650 a day (Outside IR35) We're supporting a leading UK financial services organisation in the search for an experienced JWT / JSON Developer to join a high-performing engineering team on an initial 6-month contract. This role will focus on authentication, authorisation and secure service-to-service communication across a large-scale digital platform. You'll be working on OAuth 2.0 and OpenID Connect (OIDC) implementations, JWT-based authentication, and integrations with identity providers within a modern cloud-native environment. Key Responsibilities Develop and maintain authentication and authorisation services Implement OAuth 2.0 and OIDC integrations with identity providers Work with JSON Web Tokens (JWTs), including issuance, validation, signing and key management Contribute to CI/CD pipelines and trunk-based delivery practices...

JWT/JSON Developer Location: London - Hybrid/2 days per week onsite Contract Length: 6 months Day Rate: Up to £650 a day (Outside IR35) We're supporting a leading UK financial services organisation in the search for an experienced JWT/JSON Developer to join a high-performing engineering team on an initial 6-month contract. This role will focus on authentication, authorisation and secure service-to-service communication across a large-scale digital platform. You'll be working on OAuth 2.0 and OpenID Connect (OIDC) implementations, JWT-based authentication, and integrations with identity providers within a modern cloud-native environment. Key Responsibilities Develop and maintain authentication and authorisation services Implement OAuth 2.0 and OIDC integrations with identity providers Work with JSON Web Tokens (JWTs), including issuance, validation, signing and key management Contribute to CI/CD pipelines and trunk-based delivery practices Write and review...

JWT / JSON Developer Location: London - Hybrid / 2 days per week onsite Contract Length: 6 months Day Rate: Up to £650 a day (Outside IR35) We 're supporting a leading UK financial services organisation in the search for an experienced JWT / JSON Developer to join a high-performing engineering team on an initial 6-month contract. This role will focus on authentication, authorisation and secure service-to-service communication across a large-scale digital platform. You 'll be working on OAuth 2.0 and OpenID Connect (OIDC) implementations, JWT-based authentication, and integrations with identity providers within a modern cloud-native environment. Key Responsibilities Develop and maintain authentication and authorisation services Implement OAuth 2.0 and OIDC integrations with identity providers Work with JSON Web Tokens (JWTs), including issuance, validation, signing and key management Contribute to CI/CD pipelines and trunk-based...

Senior Java Developer - Outside IR35 - Up to £700 per day We have partnered with a leader in the financial services sector who is looking for experienced Senior Java Engineers to join their Settlements team . This is a hands-on engineering role focused on developing and enhancing software supporting complex post-trade and settlement workflows . you'll work as part of an experienced engineering team, contributing to both new and existing systems within a fast-moving financial markets environment. The Role Develop and maintain Server Side Java/JVM applications supporting settlement and post-trade processes. Build robust, scalable services using Spring and Spring Boot . Work across greenfield and brownfield development projects. Collaborate with engineers and business stakeholders to understand requirements and deliver effective solutions. Contribute to technical design, development, testing and production delivery. Work with Kubernetes, event-driven...

Contract Python Engineers – 3–6 Month Contracts London / Hybrid | £650–£750 pd Outside IR35 I’m working with a heavily VC-backed financial services platform that is going through a really exciting period of global expansion. They’ve built their own technology offering using modern Python and are disrupting a traditionally legacy-heavy sector. They’re now looking to bring in three technically strong Python Engineers on an initial 3–6 month contract, with the potential for further work. This is a small, highly technical team, so they’re looking for engineers who can genuinely stand on their own two feet. You’ll be expected to work across the development lifecycle rather than relying on someone else to handle areas such as testing, architecture or data structures. They’d particularly like to speak with people who have worked in smaller engineering teams, start-ups or scale-ups, where you’ve had to take ownership rather than being one small part of a huge...

Prompt Engineer (Claude/Claude Code) - Mortgage Sales £695 per day Outside IR35 Ideally London 1 day per week/Can be fully remote A leading UK mortgage technology provider is looking for a Prompt Engineer with strong Claude and Claude Code experience to support the development of a new Mortgage Sales System. This is a new role within the business. You'll work with stakeholders across the business to understand their requirements and translate them into high-quality prompts, instructions and AI workflows. You'll then test and refine them so the outputs are accurate, consistent and reliable. You'll work closely with the development team throughout delivery. This is not a developer role. A separate team builds and tests the application code, and your focus is on making sure the requirements, prompts and AI outputs are right. What you'll need: Strong hands-on experience with Claude and Claude Code Prompt engineering experience, including prompt design and optimisation...

DV Cleared Software Engineer London | onsite Outside IR35 | Long-term Contract Active DV Clearance Required I'm working with an organisation delivering a long term programme within UK Government that is looking to add experienced Software Engineers with strong Python skills to its team. The role will involve designing, developing and improving software solutions within a highly secure technical environment. You'll be working alongside experienced engineers and technical stakeholders on challenging projects where there is plenty of scope to contribute ideas and influence how solutions are built. What we're looking for: Strong commercial Python development experience Background as a Software Engineer, Python Developer or Application Developer Experience developing applications in Linux environments Knowledge of modern software engineering and development practices Exposure to data processing, messaging, integration or workflow-based systems Comfortable tackling...

TypeScript Engineer £500- £550 per day Outside IR35 1 day onsite - London We 're working with a large international travel and transport organisation that is modernising its digital ecosystem following the consolidation of multiple business units. The company is investing heavily in next-generation data and middleware platforms, and they 're looking for a TypeScript Engineer to help shape the services and tooling behind this transformation. The team 's mission is to replace legacy systems with clean, event-driven services and provide consistent, reliable data to applications across the business - from customer-facing products to operational systems. The Role You 'll be joining a multidisciplinary engineering team focused on building backend and occasionally frontend components using modern TypeScript across Node.js and React/Next.js. The role centres on developing APIs, event-driven services, and internal tools that support large-scale, cloud-hosted...

Palantir Engineer £650-750 p/d Outside IR35 | 3-6 months | London / Remote Ncounter is supporting a major healthcare transformation programme and is looking for experienced Palantir Engineers to help develop data-driven applications across a complex and highly regulated environment. The programme is focused on improving how operational and service data is structured, connected and used, giving teams better access to information and supporting more effective decision-making across healthcare services. This is a hands-on engineering role, working within an established delivery team across several concurrent workstreams. You will build applications within the Palantir ecosystem, translating complex healthcare and operational requirements into practical workflows, applications and data models. The role: Build and enhance applications using Palantir, with a particular focus on SEQ Develop workflows, forms and user-facing applications around real...

QA / Integration Tester - Commodity Trading - London - Outside IR35 A leading energy company is seeking a hands-on QA / Integration Tester to support its LNG Technology team in the implementation of a new trading platform. Overview This role sits at the heart of a major platform rollout, focusing on end-to-end integration testing across an ETRM platform and its connected trading and operational systems. You’ll play a critical role in ensuring system stability, data integrity, and workflow accuracy across the broader LNG trading ecosystem. Key Responsibilities • Own and execute integration testing for the trading platform • Validate cross-system workflows and data flows across connected energy trading systems • Identify, document, and track defects through to resolution • Work closely with developers, business analysts, and stakeholders to ensure quality delivery • Operate as the sole QA resource on the project, driving testing...