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9 api developer jobs found

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api developer £400 - £500 Greater London
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London  (7) Remote  (1)
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 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 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 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 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 18, 2026
up to 6 Months
React Developer at IO Associates, London, 3 Months, £400-£420 per day
£400 - £420 per day
Outside Spy London, UK
React Developer Remote with very occasional client visits £400pd to £420pd - Outside IR35 3 - 6 month contract Our client, an established and successful Consultancy are looking for a number of mid-level Developers to join them on a contract basis With head offices in the north of the UK and branches spreading across the globe, they're a dynamic technology consultancy leader with a dedicated team of professionals, partnering with sector leaders After recently winning a large public sector project they are creating a whole new team and need people who are able to start no later than March 16th. This is a fully hands on role where you will work as part of an established successful team, primarily working with React and Typescript technologies We are looking for: Expert knowledge of React Strong proficiency in JavaScript (ES6+), HTML5, CSS3, and responsive UI engineering. Experience with Redux or other state management libraries. Strong understanding of Front End...
Outside Spy
Mar 16, 2026
Duration not stated
React Native Developer - REMOTE at Standard 8 Recruitment Ltd, London, £350 to £400 per Day
£350 - £400 per day
Outside Spy Remote (London, UK)
Contract React Native Developer (Outside IR35) Remote | 6–8 Week Initial Project + Ongoing Retainer We’re looking for an experienced React Native Developer to support an established mobile application used across Android and iOS. This is an initial 6–8 week project focused on delivering two key enhancements to an existing production application, with the opportunity for ongoing work (approx. one week per month) for continued development and maintenance. You’ll be joining a mature product environment and working closely with backend engineers and the product team to deliver improvements to a live application. Key Responsibilities Develop and enhance features within an existing React Native mobile application Work across both Android and iOS platforms Collaborate with backend developers to integrate APIs and services Contribute to improvements within a large, production-level codebase Deliver clean, maintainable and...
Outside Spy
Mar 13, 2026
Duration not stated
Senior Python Engineer at Gravitas Recruitment Group Ltd, City of London, £250-£400 per day
£250 - £400 per day
Outside Spy City of London, UK
Overview We are seeking a Senior Python Developer to support a large-scale digital transformation programme. The role focuses on building reliable Back End services, improving system performance, and contributing to a modern, scalable engineering environment. The client is open to strong EU-based talent. Role Detail: Contract Length: 3-6 months Rate: £250-400/day Outside IR35 (Depending on experience) Work Model: Fully Remote Key Skills and Experience Strong commercial experience with Python (Django) Solid understanding of REST APIs , microservices, and Back End architecture. Experience with cloud environments (AWS & Azure). Familiarity with CI/CD pipelines and modern DevOps practices. Strong understanding of relational and/or PostgreSQL. Ability to work in distributed teams and communicate clearly. Experience with Typescript and Svelte Good problem-solving skills and attention to detail. Nice to Have Experience with containerisation (Docker,...
Outside Spy
Mar 10, 2026
Duration not stated
Artificial Intelligence Engineer at LT Harper Recruitment Group, London Area, £500 per day
£500 per day
Outside Spy London Area, United Kingdom
AI Engineer (Contract) – £500/day Outside IR35 📍 Canary Wharf, London (3 days onsite) 🇬🇧 UK-based applicants only We’re looking for experienced AI Engineers who think holistically, automate relentlessly, and know how to turn modern AI capabilities into production-grade, high-impact applications . Our AI organisation is building real-world AI products that deliver business value at speed. This role is ideal for seasoned engineers who combine strong software engineering fundamentals with a pragmatic, hands-on approach to AI tooling and infrastructure. What you’ll be doing Designing, building, and maintaining production-grade AI applications using modern engineering practices (CI/CD, testing, observability, cloud-native design). Developing reusable AI platforms and tools (e.g. conversational bots, AI-powered search, unstructured data processing, GenAI solutions). Working in cross-functional, embedded teams with business stakeholders to rapidly deliver...
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