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58 Contract API jobs in Hertfordshire + 20 miles
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Full Stack Engineer TypeScript API React
Full Stack Engineer TypeScript API React
Client Server
Shoreditch, East London (E1), EC2A
£50000 - £60000 per annum + benefits
Full Stack Engineer / Developer (TypeScript API React) London / WFH to £60k - Apply now to find out more about this Full Stack Engineer / Developer (TypeScript API React) opportunity.
Full Stack Engineer / Developer (TypeScript API React) London / WFH to £60k - Apply now to find out more about this Full Stack Engineer / Developer (TypeScript API React) opportunity.
PREMIUM
Senior Backend Engineer TypeScript Node API
Senior Backend Engineer TypeScript Node API
Client Server
The City, City of London (EC4), EC2V
£85000 - £100000 per annum + shares + benefits
Senior Backend Engineer / Developer (TypeScript Node API) London / WFH to £100k
Senior Backend Engineer / Developer (TypeScript Node API) London / WFH to £100k
PREMIUM
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Strong knowledge of API integration.
Strong knowledge of API integration.
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Strong grasp of databases (SQL/NoSQL) and API integrations
Strong grasp of databases (SQL/NoSQL) and API integrations
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Skilled in building robust, optimized API endpoints.
Skilled in building robust, optimized API endpoints.
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Applications Support Analyst / Engineer
Applications Support Analyst / Engineer
Kudos Partners
Datchet Common, Slough (SL3), SL3
£75,000 per annum plus 12% bonus - generous benefits package
API support and monitoring tools (e.g., SolarWinds, AzureAppInsights)
API support and monitoring tools (e.g., SolarWinds, AzureAppInsights)
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Proficient in automation tooling relevant to SAP & developing scripts (API & UI level)
Proficient in automation tooling relevant to SAP & developing scripts (API & UI level)
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Familiarity with microservices, API integration patterns and cloud concepts such as AWS.
Familiarity with microservices, API integration patterns and cloud concepts such as AWS.
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Role - .Net Engineer - Location - Hybrid, Home and twice a month onsite (multiple locations) Contract - Initial 3 months, high probability of extension to 2027 - Rate - £475 to £525 per day - Start - ASAP - This role has been deemed Inside IR35. You must hold active SC Clearance to be eligible for this role. The Opportunity - We are working in partnership with a leading defence systems integrator to recruit a .Net Engineer for a major long-term programme of work. This is an exciting opportunity to join a highly capable engineering team delivering innovative software solutions across complex and mission-critical environments. If you’re looking to broaden your technical exposure; particularly across modern data platforms and integration technologies—this role offers the chance to grow within a dynamic, fast-moving setting where no two challenges are the same. The Role
Role - .Net Engineer - Location - Hybrid, Home and twice a month onsite (multiple locations) Contract - Initial 3 months, high probability of extension to 2027 - Rate - £475 to £525 per day - Start - ASAP - This role has been deemed Inside IR35. You must hold active SC Clearance to be eligible for this role. The Opportunity - We are working in partnership with a leading defence systems integrator to recruit a .Net Engineer for a major long-term programme of work. This is an exciting opportunity to join a highly capable engineering team delivering innovative software solutions across complex and mission-critical environments. If you’re looking to broaden your technical exposure; particularly across modern data platforms and integration technologies—this role offers the chance to grow within a dynamic, fast-moving setting where no two challenges are the same. The Role
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Lead .Net Software Developer
Lead .Net Software Developer
Hireful
Milton Keynes, Buckinghamshire, MK9
£65k - £75k base salary + bonus and great benefits
Are you a hands-on Lead or Senior .Net Developer ready to shape architecture and guide talented developers? Want a hybrid role with 3 days WFH? This is your chance to stay close to the code while making key technical decisions that drive real business impact. You'll join a collaborative, forward-thinking team building cutting-edge products — with the support, tools, and flexibility to thrive. Role: Lead Software Developer, Senior .Net Developer, Software Engineering Manager, Senior Full Stack Developer, Lead .Net Developer, Lead Software Engineer, Senior C# Developer - Salary: £65k - £75k base + Bonus - Benefits: 5% pension, 25 days holiday, 2 wellbeing days, Christmas shutdown, private healthcare, life assurance, cinema tickets & more - Location: Milton Keynes – Hybrid (2 days a week in office) If you’ve got strong .Net (C#) experience and skills in GitHub, APIs, Pos
Are you a hands-on Lead or Senior .Net Developer ready to shape architecture and guide talented developers? Want a hybrid role with 3 days WFH? This is your chance to stay close to the code while making key technical decisions that drive real business impact. You'll join a collaborative, forward-thinking team building cutting-edge products — with the support, tools, and flexibility to thrive. Role: Lead Software Developer, Senior .Net Developer, Software Engineering Manager, Senior Full Stack Developer, Lead .Net Developer, Lead Software Engineer, Senior C# Developer - Salary: £65k - £75k base + Bonus - Benefits: 5% pension, 25 days holiday, 2 wellbeing days, Christmas shutdown, private healthcare, life assurance, cinema tickets & more - Location: Milton Keynes – Hybrid (2 days a week in office) If you’ve got strong .Net (C#) experience and skills in GitHub, APIs, Pos
FEATURED
Vitest/Jest, Docker, CI/CD (GitHub Actions), Shadcn/MUI, MongoDB, microservices, Cloudflare/CDNs, Firebase, Google Maps API, startup experience.
Vitest/Jest, Docker, CI/CD (GitHub Actions), Shadcn/MUI, MongoDB, microservices, Cloudflare/CDNs, Firebase, Google Maps API, startup experience.
Java Software Engineer - Tech for Good
Java Software Engineer - Tech for Good
Client Server
The City, City of London (EC3), EC3V
£85000 - £100000 per annum + benefits
Apply now to find out more about this Java Software Engineer / Developer (Java Angular SQL API) opportunity.
Apply now to find out more about this Java Software Engineer / Developer (Java Angular SQL API) opportunity.
PREMIUM
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Solid understanding of system design principles and API development.
Solid understanding of system design principles and API development.
PREMIUM
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Interact with API systems to query and retrieve data for analysis. * Knowledge of querying API systems.
Interact with API systems to query and retrieve data for analysis. * Knowledge of querying API systems.
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Associate Engineering Manager - Salesforce
Associate Engineering Manager - Salesforce
The Stepstone Group
Southwark, South East London (SE1), SE1 0TA
Competitive salary
Occasionally, being able to lend hands-on support to the team working on and using the following technologies: Salesforce (APEX classes, metadata API, etc.) and Salesforce CLI (SFDX), Visual Studio Code, Git, CI/CD, AWS * Technical knowledge and understanding of Salesforce (APEX classes, metadata API, etc.) and Salesforce CLI (SFDX); Sales cloud essential,?marketing cloud desirable, CPQ cloud?desirable,?
Occasionally, being able to lend hands-on support to the team working on and using the following technologies: Salesforce (APEX classes, metadata API, etc.) and Salesforce CLI (SFDX), Visual Studio Code, Git, CI/CD, AWS * Technical knowledge and understanding of Salesforce (APEX classes, metadata API, etc.) and Salesforce CLI (SFDX); Sales cloud essential,?marketing cloud desirable, CPQ cloud?desirable,?
NEWPREMIUMEQUALITY BOOST
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Get your API on!
Get your API on!
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As a Technical Business Analyst you will be working on our consulting projects, primarily designing RESTful API services. * Capture and curate business requirements and system documentation in JIRA/Confluence, user stories, API design, API enhancements * Design RESTful web APIs for new and existing products in an API first context, in accordance with strategic guidance provided by the technical architect. Specify contracts for messaging and web services, primarily using JSON Schema and Open API Specification (Swagger), respectively. * Comfortable working with source code (Git) to manage API specifications. * Able to work with a web API testing tool such as Postman, including crafting authentication tokens
As a Technical Business Analyst you will be working on our consulting projects, primarily designing RESTful API services. * Capture and curate business requirements and system documentation in JIRA/Confluence, user stories, API design, API enhancements * Design RESTful web APIs for new and existing products in an API first context, in accordance with strategic guidance provided by the technical architect. Specify contracts for messaging and web services, primarily using JSON Schema and Open API Specification (Swagger), respectively. * Comfortable working with source code (Git) to manage API specifications. * Able to work with a web API testing tool such as Postman, including crafting authentication tokens
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Business Analyst
Business Analyst
REC SOLUTIONS LIMITED
The City, City of London (EC4), EC4N
Competitive base salary plus bonus and benefits
Proficiency in creating and maintaining clear, comprehensive technical documentation and API specifications.
Proficiency in creating and maintaining clear, comprehensive technical documentation and API specifications.
NEW
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Windsor, UK - Will the role be 100% remote, Hybrid or 100% office? (Mandatory) Hybrid (visit to office once every week) to begin with - Is BGC required to completed before joining?(Y/N) * Participate in refining and scoping upcoming sprint work. * Assist solution architects with technical design and breaking down complex tasks. * Accountable for timely delivery of assigned tickets, meeting acceptance criteria. * Conduct spikes/investigations into innovative technologies for future project viability. * Ensure teammates' work meets code quality standards through reviews. * Coordinate with other teams for integrations, ensuring alignment of tasks and APIs. * Work with the QA team to investigate and resolve issues. * Mentor junior team members, providing assistance with tasks and problem-solving. * At least 5+ years Salesforce, both declarative and programmatic * Sales an
Windsor, UK - Will the role be 100% remote, Hybrid or 100% office? (Mandatory) Hybrid (visit to office once every week) to begin with - Is BGC required to completed before joining?(Y/N) * Participate in refining and scoping upcoming sprint work. * Assist solution architects with technical design and breaking down complex tasks. * Accountable for timely delivery of assigned tickets, meeting acceptance criteria. * Conduct spikes/investigations into innovative technologies for future project viability. * Ensure teammates' work meets code quality standards through reviews. * Coordinate with other teams for integrations, ensuring alignment of tasks and APIs. * Work with the QA team to investigate and resolve issues. * Mentor junior team members, providing assistance with tasks and problem-solving. * At least 5+ years Salesforce, both declarative and programmatic * Sales an
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API Development & Integration - Proficient in designing and building RESTful APIs using FastAPI, Flask, or Django REST Framework for exposing AI models and automation services. Experience with API authentication (OAuth, JWT), rate limiting, error handling, API documentation (Swagger/OpenAPI), webhooks, and integrating disparate systems to create seamless automated workflows. Ability to assess when RPA vs. API integration vs. AI solutions are most appropriate, and experience building hybrid automation solutions combining multiple technologies.
API Development & Integration - Proficient in designing and building RESTful APIs using FastAPI, Flask, or Django REST Framework for exposing AI models and automation services. Experience with API authentication (OAuth, JWT), rate limiting, error handling, API documentation (Swagger/OpenAPI), webhooks, and integrating disparate systems to create seamless automated workflows. Ability to assess when RPA vs. API integration vs. AI solutions are most appropriate, and experience building hybrid automation solutions combining multiple technologies.
NEW
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Senior Android Engineer (Native Integration & Security)
Senior Android Engineer (Native Integration & Security)
Ventula Consulting Limited
The City, City of London (EC3), EC3V 9DU
Up to £150,000 per annum
Build a robust, efficient, and scalable client-side API integration layer to consume real-time security signals (like our proprietary Scam_Score) from the AI Core. Partner with the Senior Backend Engineer (Application & AI Orchestration) to define the API contracts and real-time data flow needed to power the Security Shield.
Build a robust, efficient, and scalable client-side API integration layer to consume real-time security signals (like our proprietary Scam_Score) from the AI Core. Partner with the Senior Backend Engineer (Application & AI Orchestration) to define the API contracts and real-time data flow needed to power the Security Shield.
Senior Android Engineer (Native Integration & Security)
Senior Android Engineer (Native Integration & Security)
Ventula Consulting Limited
The City, City of London (EC3), EC3V 9DU
Up to £150,000 per annum
Build a robust, efficient, and scalable client-side API integration layer to consume real-time security signals (like our proprietary Scam_Score) from the AI Core. Partner with the Senior Backend Engineer (Application & AI Orchestration) to define the API contracts and real-time data flow needed to power the Security Shield.
Build a robust, efficient, and scalable client-side API integration layer to consume real-time security signals (like our proprietary Scam_Score) from the AI Core. Partner with the Senior Backend Engineer (Application & AI Orchestration) to define the API contracts and real-time data flow needed to power the Security Shield.
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Remote Head of AI Software Development - Python, Azure, AI Platform
Remote Head of AI Software Development - Python, Azure, AI Platform
Recruitment Revolution
City of London (EC1), EC2A 4NE
Competitive Salary + 20% bonus + Equity
• Shape the platform architecture, ensuring scalable, secure, cloud-native design across AI, data, and API layers.
• Shape the platform architecture, ensuring scalable, secure, cloud-native design across AI, data, and API layers.
Senior Backend Engineer - Systmes Design - Golang
Senior Backend Engineer - Systmes Design - Golang
Ventula Consulting Limited
City of London (EC1)
Up to £160,000 per annum
We are seeking a foundational engineer to own our single greatest strategic asset: our unique, privileged access to network-level intelligence via the GSMA CAMARA API standard. * Own and buildthe Security Signal Ingestion path, the secure, low-latency, and out-of-band data channel connecting to our founding members' network API gateways. * Ensureall network API integrations meet the stringent P99 latency budgets (e.g., < 150ms) required to support our sub-500ms Time-to-Trust product goal. * Collaboratewith the platform team to build a parallel development path using mocked data to mitigate risks of network API delays. * Deep understanding of API design(REST, gRPC, Webhooks) and API security (OAuth 2.0, mTLS, JWTs).
We are seeking a foundational engineer to own our single greatest strategic asset: our unique, privileged access to network-level intelligence via the GSMA CAMARA API standard. * Own and buildthe Security Signal Ingestion path, the secure, low-latency, and out-of-band data channel connecting to our founding members' network API gateways. * Ensureall network API integrations meet the stringent P99 latency budgets (e.g., < 150ms) required to support our sub-500ms Time-to-Trust product goal. * Collaboratewith the platform team to build a parallel development path using mocked data to mitigate risks of network API delays. * Deep understanding of API design(REST, gRPC, Webhooks) and API security (OAuth 2.0, mTLS, JWTs).
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Oracle Fusion Cloud Sr. Technical Integration Manager
Oracle Fusion Cloud Sr. Technical Integration Manager
Indotronix Avani UK Ltd
St James, South West London (SW1), SW1A
Unspecified
Fusion Cloud Products: Deep knowledge of Oracle Integration Cloud and other relevant integration requirements e.g., XSLT transformations, API security, interface error handling with practical design, configuration, and testing experience.
Fusion Cloud Products: Deep knowledge of Oracle Integration Cloud and other relevant integration requirements e.g., XSLT transformations, API security, interface error handling with practical design, configuration, and testing experience.