57 api developer jobs found

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...

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...

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...

Microsoft Teams App Developer/Microsoft 365 Solutions Developer Outside IR35 Contract Hybrid - High Wycombe Contract: Outside IR35 Location: Hybrid (High Wycombe - on-site as required) Start: ASAP Duration: Initial contract with extension potential The Opportunity We are looking for an experienced Microsoft Teams App Developer to deliver a custom Real Time meeting, microphone, and voting system built directly into Microsoft Teams . This project replaces traditional dedicated conference and voting hardware with a modern, software-based solution. You'll be building both the delegate-facing Teams app used in live meetings and the administrative control systems used to manage speakers, microphones, and voting in real time. This is a specialist contract role requiring deep Microsoft Teams platform experience , Real Time systems knowledge, and strong enterprise UX instincts. What You'll Be Working On Delegate-Facing Teams Application Design and...

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...

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)

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)

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...

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)

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)

Python Developer - UK Remote Contract - Outside IR35 | United Kingdom | Remote | £Negotiable We're working with a leading agile digital consultancy on this exciting opportunity. We are looking for a high-calibre Full Stack Contractor to spearhead a business-critical development programme over the next 12 months, delivering sophisticated digital solutions at scale. This is a chance to leverage your expertise in Python and Vue.js within a high-impact environment where clean code and architectural best practices are the standard. You will join a distributed engineering team dedicated to building modern, scalable applications that solve complex real-world problems. The Role • Lead the design and delivery of robust backend services and microservices using Python. • Build and enhance high-performance, responsive user interfaces using Vue.js for enterprise-grade applications. • Collaborate closely with Product Owners and UX Designers to translate complex...

Role: Senior Developer / Founding Engineer Contract Opportunity Outside IR35 UK or Europe Tech: React, React Native, Node, TypeScript, AWS Start date: Immediate Wedo is working with a pre-seed early stage start up who is building a mobile banking platform. The product already has a v1 application live with test users, which provides a solid starting point. However, there was limited handover, so part of this role will involve understanding the existing system and rationalising parts of the architecture as the product evolves. The immediate focus for the role is integrating a Banking-as-a-Service provider (likely ClearBank) and building the financial infrastructure required to support the product’s core mission. This includes: Designing and building the ClearBank API integration Supporting virtual accounts, payment blocking and transaction monitoring Handling webhooks and financial transaction data Extending the GraphQL schema and DynamoDB model...

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...

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.

.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.

Job Title: BackEnd Developer Location: Remote Day Rate: £400 per day (Outside ir35) Job Position: Contract We are looking for a strong BackEnd Contractor to help handle production issues. This includes working with the company’s clients and customer success team to identify the source of a technical problem and then fixing those problems. This role covers a lot of technologies, from UI, React, system configuration, Node.js backend code, databases, and AWS hosting. So this is a great opportunity to learn and expand all those skills. The right candidate needs to be able to hit the ground running, a good problem solver, and can prioritise what is important and get it done. Experience needed as a Back End Developer: 5+ years of Node.js development Experience using AI Tools such as Cursor, Claude Code or similar Type Script/React/Strong JavaScript skills REST API development SQL Git

Job Title: Mavenir Techno-Functional Oracle R12 resource Location: Remote Job Type: 3 months- Outside IR35 Role overview Mavenir Techno-Functional Oracle R12 resource Key Responsibilities Assess current state: Review existing bank integrations leveraging Talend/Oracle EBS integration and define reusable patterns for new bank integration. Build & configure: Develop/modify Bank integration jobs and required Oracle EBS R12 configurations to enable banking interfaces. Connectivity validation: Coordinate onboarding and validate connectivity for ~70 Banks accounts (credentials/certs, access, file exchange/tests). Set up in GL & Cash management the appropriate modules for each account based on account activities (AR/AP/IC ). Testing & go-live: Run SIT/UAT support, reconciliation checks, cutover planning, and hypercare. Documentation: Produce design docs, mappings, runbooks, and handover materials. Technical Experience (Required)...

.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.

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.

Boomi Integration Developer - Contract Overview We are looking for an experienced Boomi Integration Developer to support a series of integration projects. This is a 3‑month contract, fully remote, and operating outside IR35. Key Responsibilities * Design, develop, and maintain integrations using the Boomi platform * Work closely with internal teams to understand integration requirements * Troubleshoot and optimise existing Boomi processes * Support project delivery across multiple systems and data sources * Ensure best practice, documentation, and smooth handover at the end of the engagement Requirements * Proven experience as a Boomi Integration Developer * Strong understanding of integration patterns and API development * Ability to work independently and deliver in a fast‑paced environment * Excellent communication and problem‑solving skills * Boomi certifications beneficial but not essential Contract Details * Length: 3 months * Location: Remote * IR35 Status: Outside IR35...