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37 api developer jobs found

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api developer Greater London
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Outside Spy
Mar 12, 2026
Duration not stated
Mid-Level .NET / Full Stack Developer – Hybrid – £450/day Outside IR35 | C# | Azure | Event-Driven Systems | Payments | API-Driven at VirtueTech Recruitment Group, London Area, £450 per day
£450 per day
Outside Spy London Area, United Kingdom
Mid-Level .NET / Full Stack Developer – Hybrid – £450/day Outside IR35 | C# | Azure | Event-Driven Systems | Payments | API-Driven We have a great opportunity for a Mid-Level .NET / Full Stack Developer to join a growing payments company. As a .NET Developer , you’ll be working as part of an experienced engineering team building and scaling a high-throughput payments platform. The business is entering its next phase of growth, launching new products, enabling new partner integrations, and expanding a platform that already powers multiple live financial services products used globally. You’ll be contributing to a modern, cloud-native platform built with .NET and Azure , designed around API-first architecture and event-driven microservices . The platform supports complex payment flows, partner integrations, and high-volume transaction processing. This is a hands-on development role where you’ll work closely with senior engineers to deliver reliable, scalable...
Outside Spy
Mar 12, 2026
Duration not stated
Lead .NET/Full Stack Developer - Hybrid - Up to £700/day Outside IR35 | C# | Azure | Event Driven Systems | Payments | API Driven at VirtueTech Recruitment Group, London Area, £700 per day
£700 per day
Outside Spy London Area, United Kingdom
Lead .NET/Full Stack Developer - Hybrid - £700/day Outside IR35 | C# | Azure | Event Driven Systems | Payments | API Driven We have a unique opportunity for a Lead .NET/Full Stack Developer to join a payments company. As the Lead .NET/Full Stack Developer , you’ll play a key role in shaping and scaling a high-throughput payments platform as the business enters its next phase of growth. This includes launching new products, enabling new partner integrations, and expanding a platform that already powers multiple live financial services products used globally. You’ll be building on top of a modern, cloud-native platform built with .NET and Azure , designed around API-first architecture and event-driven microservices . The platform supports complex payment flows, partner integrations, and high-volume transaction processing. This is a hands-on technical role where you’ll help drive engineering best practices, contribute to architectural decisions, and mentor...
Outside Spy
Mar 12, 2026
Duration not stated
Senior .NET / Full Stack Developer – Hybrid – £600/day Outside IR35 | C# | Azure | Event-Driven Systems | Payments | API-Driven at VirtueTech Recruitment Group, London Area, £600 per day
£600 per day
Outside Spy London Area, United Kingdom
Senior .NET / Full Stack Developer – Hybrid – £600/day Outside IR35 | C# | Azure | Event-Driven Systems | Payments | API-Driven We have a unique opportunity for a Senior .NET / Full Stack Developer to join a payments company. As a Senior .NET / Full Stack Developer , you’ll play a key role in building and scaling a high-throughput payments platform as the business enters its next phase of growth. This includes launching new products, enabling new partner integrations, and expanding a platform that already powers multiple live financial services products used globally. You’ll be building on top of a modern, cloud-native platform built with .NET and Azure , designed around API-first architecture and event-driven microservices . The platform supports complex payment flows, partner integrations, and high-volume transaction processing. This is a hands-on senior engineering role where you’ll contribute to architectural discussions, drive engineering best...
Outside Spy
Mar 19, 2026
Duration not stated
Software Engineer at Haystack, Greater London, £500-£600 per day
£500 - £600 per day
Outside Spy Greater London, England, United Kingdom
ComfyUI Workflow Developer | London | Remote-Friendly | £500 - £600 We're working with a high-end creative agency specializing in hyper-realistic CGI for global luxury brands on this exciting opportunity. We are looking for a technical visionary to bridge the gap between AI experimentation and high-end production pipelines. This role is about more than just generating pretty images; it’s about engineering robust, scalable AI architectures using ComfyUI, Python, and Stable Diffusion to meet the exacting standards of the luxury market. You will move from a high-impact POC sprint into a full-scale production deployment, automating asset generation that rivals traditional CGI. The Role Architect and build advanced ComfyUI workflows capable of generating high-resolution, brand-compliant assets at scale. Develop custom Python scripts and API integrations to connect AI pipelines with existing Digital Asset Management (DAM) systems. Transition from a 4-week Proof of...
Outside Spy
Mar 19, 2026
Duration not stated
RPA Developer at La Fosse Associates, London, £575-£600 per day
£575 - £600 per day
Outside Spy London, UK
Join a transformative automation programme where your RPA expertise will streamline operations and drive efficiency across a leading organisation. Salary: £575 - 600 per day RPA Developer | Contract | (Power Automate Cloud + Graph API) Outside IR35 | £600/day | 2 days per week in London | 3-month contract (likely extension) We're supporting a large organisation on a long-running automation programme and looking for an experienced RPA Developer with strong Power Automate expertise. This role focuses on building and enhancing automation workflows using Power Automate Cloud, integrating with enterprise systems through Graph APIs, and designing reliable automated processes that streamline operations across multiple teams. You'll be working in a fast-paced environment where you'll own automation build activity end-to-end and contribute to wider governance and optimisation. Key Responsibilities Build and maintain RPA workflows using Power Automate Cloud Develop...
Outside Spy
Mar 19, 2026
Duration not stated
RPA Developer at La Fosse Associates Limited, Greater London, £575-£600 per day
£575 - £600 per day
Outside Spy Greater London, England, UK
RPA Developer | Contract | (Power Automate Cloud + Graph API) Outside IR35 | £600/day | 2 days per week in London | 3-month contract (likely extension) We're supporting a large organisation on a long-running automation programme and looking for an experienced RPA Developer with strong Power Automate expertise. This role focuses on building and enhancing automation workflows using Power Automate Cloud, integrating with enterprise systems through Graph APIs, and designing reliable automated processes that streamline operations across multiple teams. You'll be working in a fast-paced environment where you'll own automation build activity end-to-end and contribute to wider governance and optimisation. Key Responsibilities Build and maintain RPA workflows using Power Automate Cloud Develop integrations using Graph APIs and advanced connectors Design and manage dataflows, Power Query transformations, and automation logic Implement AI Builder components where appropriate...
Outside Spy
Mar 18, 2026
Duration not stated
Azure Engineer / Architect at Now Resourcing, London Area, £Contract Rate
Outside Spy London Area, United Kingdom
Azure Engineer / Architect 6 month contract London - Hybrid £500 - £650 DOE - Outside IR35 We have multiple opportunities available for Azure Engineers / Architects to join a UK based consultancy who are delivering large digital transformation initiatives across multi-cloud environments. This is a 6 month engagement with potential for further extension. Azure API Platform Engineer Senior platform engineer to lead a multi-cloud API ecosystem, designing secure, scalable microservices and modernising legacy integrations. Also responsible for standardising architecture, improving observability, and driving best practices across teams. Must have: Strong experience with API gateway technologies Deep understanding of Kubernetes in Azure environments Integration between cloud native and legacy systems Azure Cloud Platform & SRE Engineer / Architect Senior engineer to evolve Azure cloud foundations, ensuring secure,...
Outside Spy
Mar 18, 2026
6 Months or more
Salesforce Developer at Fuel Recruitment, London, 6 Months, £500 per day
£500 per day
Outside Spy London, UK
Salesforce Developer - 6-month contract - £500 per day (Outside IR35) - Remote Apex Coding/API Integrations/Field Service Lightning/Financial Systems Integration/ITSM Key Skills/Responsibilities: Deliver Salesforce development tasks including configuration, Apex coding, and API integrations. Collaborate with DevOps and IT teams to ensure alignment and continuity. Support CI/CD pipelines, automated testing, and release management processes. Participate in Agile ceremonies and contribute to sprint planning and retrospectives. Assist in the integration of Salesforce with external systems (eg, ERP, finance, invoicing). Maintain and enhance documentation for solutions, processes, and field mappings. Ensure solutions are scalable, secure, and aligned with business requirements. Provide input into UAT and training plans for new features and releases. Stay current with Salesforce platform updates and assess applicability to the organisation. Support...
Outside Spy
Mar 17, 2026
Duration not stated
Software Engineer at Arrows, London, £Contract Rate
Outside Spy London, England, United Kingdom
Software Engineer - Golang - Go - Product - TDD - £520/£550 (Outside IR35) - Hybrid - 3 months - Immediate Starter Paying up to £550 per day (Outside IR35) We're a mission-driven tech company that builds products to help people make confident decisions about their finances and everyday services. They are looking for a strong Go Developer who is excited about working with new technologies. Essential Skills: Strong commercial experience with Golang Must have a Product first mentality Experience with observability would be great Experience configuring, deploying, and monitoring applications on AWS. TDD (Test-Driven Development) experience. API build experience is essential, especially with 3rd party API's Comfortable working with relational and NoSQL databases, including complex queries and performance optimization. Solid understanding of web design patterns, including SOLID principles. Experience working in an agile, collaborative environment. Familiarity with...
Outside Spy
Mar 17, 2026
up to 6 Months
Software Engineer at Arrows Group Professional Limited, London, 3 Months, £520-£550 per day
£520 - £550 per day
Outside Spy London, UK
Software Engineer - Golang - Go - Product - TDD - £520/£550 (Outside IR35) - Hybrid - 3 months - Immediate Starter Paying up to £550 per day (Outside IR35) We're a mission-driven tech company that builds products to help people make confident decisions about their finances and everyday services. They are looking for a strong Go Developer who is excited about working with new technologies. Essential Skills: Strong commercial experience with Golang Must have a Product first mentality Experience with observability would be great Experience configuring, deploying, and monitoring applications on AWS. TDD (Test-Driven Development) experience. API build experience is essential, especially with 3rd party API's Comfortable working with relational and NoSQL databases, including complex queries and performance optimization. Solid understanding of web design patterns, including SOLID principles. Experience working in an agile, collaborative environment. Familiarity with...
Outside Spy
Mar 13, 2026
Duration not stated
Software Engineer at Haystack, Greater London, £500-£600 per day
£500 - £600 per day
Outside Spy Greater London, England, United Kingdom
ComfyUI Workflow Developer | London | Remote-Friendly | £500 - £600 We're working with a high-end creative agency specializing in hyper-realistic CGI for global luxury brands on this exciting opportunity. We are looking for a technical visionary to bridge the gap between AI experimentation and high-end production pipelines . This role is about more than just generating pretty images; it’s about engineering robust, scalable AI architectures using ComfyUI, Python, and Stable Diffusion to meet the exacting standards of the luxury market. You will move from a high-impact POC sprint into a full-scale production deployment, automating asset generation that rivals traditional CG I. The R ole• Architect and build advanced ComfyUI workflows capable of generating high-resolution, brand-compliant assets at sca le.• Develop custom Python scripts and API integrations to connect AI pipelines with existing Digital Asset Management (DAM) syste ms.• Transition from a 4-week...
Outside Spy
Mar 12, 2026
Duration not stated
SC Cleared Java Developer at TechShack, London Area, £600–£675 per day
£600–675 per day
Outside Spy London Area, United Kingdom
Java Developer - SC Cleared Location: London (1–2 days onsite per month) Contract: Outside IR35 Rate: £600–£675 per day Duration: 12 Month Contract Start: Immediate / Short Notice Preferred Eligibility: Active SC Clearance required (DV clearance ideally) Overview An experienced Java Developer is required to build and maintain scalable, high-performance applications within a secure public sector environment. Requirements Strong experience with Java & Springboot Solid Java back-end development experience Experience working in public sector Strong understanding of API integration and system design Active SC Clearance required (DV clearance ideally)
Outside Spy
Mar 12, 2026
Duration not stated
SC Cleared Software Engineer at TechShack, London Area, £650–£700 per day
£650–700 per day
Outside Spy London Area, United Kingdom
Full Stack Developer (React / TypeScript / Java) Location: London (1–2 days onsite per month) Contract: Outside IR35 Rate: £650–£700 per day Duration: 12 Month Contract Start: Immediate / Short Notice Preferred Eligibility: Active SC Clearance required (DV clearance ideally) Overview An experienced Full Stack Developer is required to build and maintain scalable, high-performance applications within a secure public sector environment. The role requires a 50/50 split across front-end and back-end development . Requirements Strong experience with React and TypeScript Solid Java back-end development experience Experience working in a full stack capacity (approx. 50/50 front-end/back-end) Strong understanding of API integration and system design Active SC Clearance required (DV clearance ideally)
Outside Spy
Mar 12, 2026
6 Months or more
SharePoint/Microsoft 365 Application Developer at SR2 - Socially Responsible Recruitment, London, 6 Months, £330-£350 per day
£330 - £350 per day
Outside Spy London, UK
SharePoint/Microsoft 365 Application Developer £330-£350 per day | Outside IR35 | Fully Remote | 6-Month Rolling Contract | April Start We're looking for an experienced SharePoint/Microsoft 365 Developer to support digital transformation projects and deliver modern collaboration solutions across Microsoft 365. You'll design and build solutions across SharePoint Online, Power Platform, and wider Microsoft 365 services , helping organisations improve collaboration, automation, and productivity. What you'll be doing Build and maintain SharePoint Online sites, lists, libraries, and workflows Develop applications using Power Apps and Power Automate Create modern SharePoint components using SPFx Integrate Microsoft 365 services such as Teams, OneDrive, and Azure AD Support SharePoint migrations from Legacy environments Translate business requirements into scalable technical solutions Troubleshoot and improve SharePoint and Microsoft 365...
Outside Spy
Mar 12, 2026
6 Months or more
SC Cleared Java Dev at TechShack, London, 6 Months, £600-£675 per day
£600 - £675 per day
Outside Spy London, UK
Java Developer - SC Cleared Location: London (1-2 days onsite per month) Contract: Outside IR35 Rate: £600-£675 per day Duration: 12 Month Contract Start: Immediate/Short Notice Preferred Eligibility: Active SC Clearance required (DV clearance ideally) Overview An experienced Java Developer is required to build and maintain scalable, high-performance applications within a secure public sector environment. Requirements Strong experience with Java & Springboot Solid Java Back End development experience Experience working in public sector Strong understanding of API integration and system design Active SC Clearance required (DV clearance ideally)
Outside Spy
Mar 12, 2026
6 Months or more
SC React Java at TechShack, London, 6 Months, £650-£700 per day
£650 - £700 per day
Outside Spy London, UK
Full Stack Developer (React/TypeScript/Java) Location: London (1-2 days onsite per month) Contract: Outside IR35 Rate: £650-£700 per day Duration: 12 Month Contract Start: Immediate/Short Notice Preferred Eligibility: Active SC Clearance required (DV clearance ideally) Overview An experienced Full Stack Developer is required to build and maintain scalable, high-performance applications within a secure public sector environment. The role requires a 50/50 split across Front End and Back End development . Requirements Strong experience with React and TypeScript Solid Java Back End development experience Experience working in a full stack capacity (approx. 50/50 Front End/Back End) Strong understanding of API integration and system design Active SC Clearance required (DV clearance ideally)
Outside Spy
Mar 10, 2026
Duration not stated
Fullstack Developer at Hexwired Recruitment Limited , London, £750 to £1000 per Day
£750 - £1,000 per day
Outside Spy London, UK
Fullstack Developer – Palantir Foundry job in London – £750 - £1000 a day – London – Outside IR35 Hexwired Recruitment is recruiting for an expanding Solutions provider, now seeking Data Engineers and Fullstack Developers with solid experience working on Palantir Foundry’s data analytics dashboard. You will be working on the full product lifecycle for a range of customers within Finance, energy and more. The successful candidate must have good experience on both the API development and backend data management side of Palantir’s products. Initial 3 months with very likely extension. Outside IR35 and will require at least 3 days onsite. Key Skills: Bachelors in CS, Maths, Physics or similar 3+ commercial Palantir Foundry dashboard experience Solid experience building applications using Palantir Foundry Excellent Data Engineering experience using Palantir Foundry Company is agnostic on programming languages, Python, Java, Typescript and/or React...
Outside Spy
Mar 10, 2026
Duration not stated
Snr C#.Net Developer - Entity, AWS - 3 Months at Jump IT Recruitment , London, £450 to £500 per Day
£450 - £500 per day
Outside Spy London, UK
.Net 6, .Net 10, C#, ASP.NET, .NET Core, AWS, CDK, IaC, Cognito, S3, KMS, CI/CD, Docker, Containers, Entity, Firebase 3-month contract role. Outside IR35. £500 per day. Must be a UK based candidate. No visa sponsorship or visa transfer. Experience within Healthcare, Pharma or LifeSciences is a definite advantage. The role will involve the following: Migrate the platform to .NET 10 LTS Implement secrets management using AWS Secrets Manager Strengthen authentication and authorisation mechanisms Enhance audit trail and compliance features for healthcare regulations Improve API security, including rate limiting and CORS configuration Update Docker containers and CI/CD pipelines Establish and expand unit and integration test coverage Work with Clean Architecture patterns across the solution To start ASAP. Please email a CV to Roger at Jump IT in the first instance.
Outside Spy
Mar 10, 2026
Duration not stated
Snr C#.Net Developer - Entity, AWS - 3 Months at Jump IT Recruitment Solutions Ltd, London, £Contract Rate
Outside Spy London, UK
.Net 6, .Net 10, C#, ASP.NET, .NET Core, AWS, CDK, IaC, Cognito, S3, KMS, CI/CD, Docker, Containers, Entity, Firebase 3-month contract role. Outside IR35. £500 per day. Must be a UK-based candidate. No visa sponsorship or visa transfer. Experience within Healthcare, Pharma or Life Sciences is a definite advantage. The role will involve the following: Migrate the platform to .NET 10 LTS Implement secrets management using AWS Secrets Manager Strengthen authentication and authorisation mechanisms Enhance audit trail and compliance features for healthcare regulations Improve API security, including rate limiting and CORS configuration Update Docker containers and CI/CD pipelines Establish and expand unit and integration test coverage Work with Clean Architecture patterns across the solution To start ASAP. Please email a CV to Roger at Jump IT in the first instance.
Outside Spy
Mar 10, 2026
Duration not stated
Snr Vue.Js Developer - JavaScript, Vuetify - 3 Months at Jump IT Recruitment Solutions Ltd, London, £Contract Rate
Outside Spy London, UK
Vue.Js, JavaScript, Vuetify, API, XSS, CSRF, Vite, Webpack, GitHub, AWS, Cognito, Firebase 3-month contract role. Outside IR35. £500 per day. Must be a UK based candidate. No visa sponsorship or visa transfer. Experience within Healthcare, Pharma or Life Sciences is a definite advantage. The role will involve the following: Lead the migration from Vue.js 2 to Vue.js 3 with Composition API Migrate Vuetify 2 components to Vuetify 3 Implement frontend security best practices (CSP headers, XSS prevention) Upgrade Node.js runtime Evaluate and implement Vite as the build tool Establish testing practices using Vitest and Vue Test Utils Optimise build performance with code splitting and lazy loading Work alongside a backend developer on API integration To start ASAP. Please email a CV to Roger at Jump IT in the first instance.
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