Date posted
Commute time
Locations
Type of Company
Job types
Salaries
Locations
4 Contract API jobs in Chelmsford + 20 miles
334 exact matches jobs are outside your preferred location
)
Excellent opportunity for an experienced .NET Backend Developer to join a rapidly growing business in London, where you will play a key role in shaping the backend systems, API architecture, and cloud infrastructure that support the company's technology roadmap.
Excellent opportunity for an experienced .NET Backend Developer to join a rapidly growing business in London, where you will play a key role in shaping the backend systems, API architecture, and cloud infrastructure that support the company's technology roadmap.
)
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
)
Strong understanding of API integrations, RESTful services, and event streaming.
Strong understanding of API integrations, RESTful services, and event streaming.
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.
)
Senior Full Stack Engineer React TypeScript
Senior Full Stack Engineer React TypeScript
Client Server
The City, City of London (EC4), EC2V
£80000 - £90000 per annum + benefits
You have strong React and Redux front end skills combined with backend JavaScript, TypeScript, Node.js and API experience
You have strong React and Redux front end skills combined with backend JavaScript, TypeScript, Node.js and API experience
PREMIUM
Supplier and partner API integrations (pricing, availability, constraints, factual data) * Translate commercial, operational and customer needs into clear product, API and data requirements * Partner with engineering to design and evolve API contracts, data structures and error handling * Proven experience as a Product Manager working on platform, API, data or pricing-heavy products
Supplier and partner API integrations (pricing, availability, constraints, factual data) * Translate commercial, operational and customer needs into clear product, API and data requirements * Partner with engineering to design and evolve API contracts, data structures and error handling * Proven experience as a Product Manager working on platform, API, data or pricing-heavy products
)
Senior Software Developer Python (SC Cleared)
Senior Software Developer Python (SC Cleared)
Certes IT Service Solutions
London
£625 - £650 per day + Negotiable
Work within a multi-disciplinary product team and lead decisions on development and maintenance of a robust, scalable open data website (front end and back end); it's services and API's.
Work within a multi-disciplinary product team and lead decisions on development and maintenance of a robust, scalable open data website (front end and back end); it's services and API's.
)
Strong background in system/API design.
Strong background in system/API design.
PREMIUM
Job Title:Solution Architect Finance - Mode of Working:Hybrid - Work Location (UK & I):Luton, UK - Role Description * Lead enterprise-level design discussions as a Finance Architect * Drive solution ideation, solution design, and solution implementation involving Finance, HR, and Procurement * Directly assist in the development of a solutions architecture program * Review enterprise architecture changes and validate against best-in-class industry standards * Direct the identification and recommendation of appropriate solutions, upgrades, replacements, or decommissioning options incorporating business and technology productivity, usability, and total cost of ownership (TCO) * Manage activities that take place during solution ideation, solution design, and solution implementation * Review business context for solutions to company challenges, design to realize the vision
Job Title:Solution Architect Finance - Mode of Working:Hybrid - Work Location (UK & I):Luton, UK - Role Description * Lead enterprise-level design discussions as a Finance Architect * Drive solution ideation, solution design, and solution implementation involving Finance, HR, and Procurement * Directly assist in the development of a solutions architecture program * Review enterprise architecture changes and validate against best-in-class industry standards * Direct the identification and recommendation of appropriate solutions, upgrades, replacements, or decommissioning options incorporating business and technology productivity, usability, and total cost of ownership (TCO) * Manage activities that take place during solution ideation, solution design, and solution implementation * Review business context for solutions to company challenges, design to realize the vision
)
Strong focus on optimizing inference performance and cost (e.g., model compression, quantization, API optimization).
Strong focus on optimizing inference performance and cost (e.g., model compression, quantization, API optimization).
FEATURED
)
Secure-Linux tools & API libraries.
Secure-Linux tools & API libraries.
)
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.
)
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
)
Get your API on!
Get your API on!
Play a significant role in the design and development of our full system with embedded HSMs, client-side tools & API libraries * Familiarity with full-stack from device drivers, to client-side tools & API libraries. (Some knowledge of hardware protocols.)
Play a significant role in the design and development of our full system with embedded HSMs, client-side tools & API libraries * Familiarity with full-stack from device drivers, to client-side tools & API libraries. (Some knowledge of hardware protocols.)
)
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.
)
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
)
Other organisations may call this role Software Engineer, Software Developer, Back-End Software Engineer, Server-Side Developer, Full Stack Developer, or API Developer.
Other organisations may call this role Software Engineer, Software Developer, Back-End Software Engineer, Server-Side Developer, Full Stack Developer, or API Developer.
)
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.
)
Responsibilities include API development, system integration, dataoptimization, and performance tuning.
Responsibilities include API development, system integration, dataoptimization, and performance tuning.
)
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.
)
Principal Software Engineer - Unified Client Experience (UCX)
Principal Software Engineer - Unified Client Experience (UCX)
Hargreaves Lansdown
London
£11500 - £90000 per annum + Generous bonus, pension, PMI & more
Deep expertise in React or React Native, with hands-on experience in secure API integration, authentication flows, and frontend architecture.
Deep expertise in React or React Native, with hands-on experience in secure API integration, authentication flows, and frontend architecture.
FEATURED
Software Engineering Manager - Unified Client Experience (UCX)
Software Engineering Manager - Unified Client Experience (UCX)
Hargreaves Lansdown
London
£90000 - £115000 per annum + Generous bonus, pension, PMI and more
Strong understanding of secure API integration, authentication flows, and modern UI/UX architecture.
Strong understanding of secure API integration, authentication flows, and modern UI/UX architecture.
FEATURED
Software Engineering Manager - Unified Client Experience (UCX)
Software Engineering Manager - Unified Client Experience (UCX)
Hargreaves Lansdown
City of London (EC1)
£90000 - £115000 per annum + Generous bonus, pension, PMI and more
Strong understanding of secure API integration, authentication flows, and modern UI/UX architecture.
Strong understanding of secure API integration, authentication flows, and modern UI/UX architecture.
FEATURED
)
Familiarity with automation, API protection, or security orchestration. * Experience with API security or microservices identity patterns!
Familiarity with automation, API protection, or security orchestration. * Experience with API security or microservices identity patterns!