Contract API Design Job Vacancies

21 of 21 Contract API Design Jobs

Contract Developer - Node.js, REST API, SIP, VOIP

Bracknell, Berkshire, United Kingdom
Hybrid / WFH Options
Reed Technology
Contract Developer - Node.js development, REST API design, and SIP-based communications Duration: 3 months (Outside IR35) Location: Bracknell/Hybrid Contract Developer with deep expertise in Node.js development, REST API design, and SIP-based communications. This role is crucial for supporting the migration of legacy device management, call control, and configuration workflows to a secure, scalable … cloud environment. Day-to-day of the role: Cloud Migration & Refactoring: Analyse existing applications to identify dependencies on on-prem infrastructure and design cloud-native solutions. Refactor services to enhance scalability and reliability in the cloud. Service & API Development: Develop and maintain secure REST APIs for functionalities such as SIP authentication, call control, and real-time data interactions. … Real-Time Communication Integration: Implement and maintain robust SIP/TLS integrations, ensuring low latency and secure communications within a safety-critical environment. Data & State Management: Design and manage schemas in cloud databases, ensuring efficient data transactions and real-time state management. Security & Compliance: Oversee the migration of sensitive data to secure cloud storage solutions, ensuring compliance with GDPR More ❯
Employment Type: Contract
Rate: GBP 500 - 550 Daily
Posted:

Contract Developer - Node.js, REST API, SIP, VOIP

Bracknell, Berkshire, United Kingdom
Hybrid / WFH Options
Reed Technology
Contract Developer - Node.js development, REST API design, and SIP-based communications Duration: 3 months (Outside IR35) Location: Bracknell/Hybrid Contract Developer with deep expertise in Node.js development, REST API design, and SIP-based communications. This role is crucial for supporting the migration of legacy device management, call control, and configuration workflows to a secure, scalable … cloud environment. Day-to-day of the role: Cloud Migration & Refactoring: Analyse existing applications to identify dependencies on on-prem infrastructure and design cloud-native solutions. Refactor services to enhance scalability and reliability in the cloud. Service & API Development: Develop and maintain secure REST APIs for functionalities such as SIP authentication, call control, and real-time data interactions. … Real-Time Communication Integration: Implement and maintain robust SIP/TLS integrations, ensuring low latency and secure communications within a safety-critical environment. Data & State Management: Design and manage schemas in cloud databases, ensuring efficient data transactions and real-time state management. Security & Compliance: Oversee the migration of sensitive data to secure cloud storage solutions, ensuring compliance with GDPR More ❯
Employment Type: Contract, Temporary
Salary: £500 - £550/day
Posted:

Senior API Technical Consultant (GraphQL Specialist)

London, United Kingdom
Staffworx Limited
Senior API Technical Consultant (GraphQL Specialist) Design and build next generation of high-scale SaaS platforms. We're looking for a senior/lead engineering consultant with deep expertise in GraphQL to take a leading role in developing our robust TypeScript/Node.js backend. You will be instrumental in shaping our technical direction, driving the evolution of our … APIs, ensuring our services are resilient, scalable and secure within a cutting-edge, cloud-native environment (Helm, Kubernetes). The Deliverables Design and build sophisticated, scalable GraphQL APIs and backend services using TypeScript and Node.js. Lead the design and evolution of our API schemas, ensuring they meet the complex demands of a rapidly growing platform. Champion best … team to guide process improvements and make key architectural decisions. Experience Extensive production experience architecting and delivering complex applications with TypeScript and Node.js . Expert level GraphQL , including advanced API design, schema evolution, performance optimisation. Strong automated testing frameworks like Vitest and Playwright . Proficiency with modern DevOps tooling and cloud-native architecture, including Docker , Helm , Kubernetes . More ❯
Employment Type: Contract
Rate: market rates, outside IR35, 2 days on site
Posted:

Technical Architect

Wokingham, Berkshire, South East, United Kingdom
Queen Square Recruitment Limited
a large global consultancy, is looking for an Azure Solution Architect to play a key role in the RegDB decommission program , working closely with stakeholders and offshore teams to design, develop, and deliver high-quality Azure-based solutions. This is a hands-on role where you will combine solution design expertise with strong development and integration skills. Key … in C#/.NET Framework with strong coding and debugging skills. Experience with Azure services : Logic Apps, Functions, APIM, Event Grid, Azure Storage, Service Bus. Strong knowledge of the API/integration lifecycle , including design, deployment, and enhancement. Hands-on experience building and updating integrations/APIs in Azure Integration . Programming proficiency: JavaScript, XSLT, C#, Liquid Templates … . Expertise in RESTful & SOAP API design , APIM policy, and transformations. Skilled in API/Integration security protocols & best practices . Practical experience with Postman, API monitoring, and documentation tools . Knowledge of Open API Specification, WSDL, SOAP, XSLT . Proficiency in SQL Server and OOPs concepts . Application Insight proficiency in .NET and .NET More ❯
Employment Type: Contract
Rate: £500 per day inside IR35
Posted:

Full Stack Developer

London, South East, England, United Kingdom
Harnham - Data & Analytics Recruitment
software across the full stack, from front-end UI to back-end APIs Build and maintain performant applications using React, Next.js, and Node.js Contribute to architectural discussions and technical design decisions Collaborate with product, design, and platform teams to align on feature delivery Write clean, maintainable code and participate in peer code reviews Optimise applications for performance, scalability … stack development using React , Next.js , and JavaScript/TypeScript Proven backend engineering skills using Node.js and/or modern languages like Python , Ruby , Scala , or Rust Solid understanding of API design and integration Track record of delivering end-to-end web applications Knowledge of performance tuning and front-end optimisation Comfortable in Agile environments with CI/CD More ❯
Employment Type: Contractor
Rate: £400 - £450 per day
Posted:

Senior Java Developer

London, South East, England, United Kingdom
Proactive Appointments
a Senior Java Developer, you will play a key role in designing, developing, and maintaining enterprise-grade applications, while mentoring junior engineers and helping shape technical strategy. Key Responsibilities Design, develop, and maintain Java-based applications and services . Write clean, efficient, and well-documented code . Participate in code reviews and provide constructive feedback. Collaborate with cross-functional … teams to define, design, and deliver new features . Troubleshoot and debug complex issues. Required Qualifications Professional Java software development experience. Strong understanding of object-oriented programming and design patterns . Hands-on experience with Spring and Hibernate frameworks. Solid experience with relational databases (MSSQL, Oracle). Proven experience with RESTful API design and development . More ❯
Employment Type: Contractor
Rate: £600 - £700 per day
Posted:

Software Engineer

Edinburgh, Midlothian, Scotland, United Kingdom
FDM Group
for someone with strong technical expertise who’s ready to step up and lead by example—bringing both strategic thinking and hands-on engineering experience to the table. Responsibilities Design, develop and maintain robust, cloud-native applications across both front-end (React/JavaScript/TypeScript) and back-end (Java, Spring Boot) stacks Tackle the most complex user stories … Requirements Minimum of 8 years’ experience in a Software Engineering role using Java and Spring Boot Strong proficiency with JavaScript, React, TypeScript Understanding of RESTful APIs, microservices, and secure API design Familiarity with DevOps tools and CI/CD pipelines (e.g. Jenkins, Maven, Docker, Kubernetes, Terraform) Experience with cloud platforms (Azure, GCP, or AWS preferred) Strong understanding of More ❯
Employment Type: Contractor
Rate: £60,000 - £85,000 per annum
Posted:

Solution Architect

Bromley, London, United Kingdom
Hybrid / WFH Options
Pontoon
systems/subsystems and their interfaces while defining non-functional requirements. Collaborate with stakeholders and vendors to ensure solutions are fit for purpose and evaluate the impact of strategic design decisions. Lead the rapid shaping of high-level architecture while maintaining flexibility and modularity. Utilize best practices and templates to create comprehensive architectural designs. Work closely with Product Managers … to prioritize technology-focused backlog items. Clarify architecture for development teams and provide solution options for any challenges. Conduct design reviews to ensure all non-functional requirements are met, focusing on aspects such as security, performance, and scalability. What We're Looking For: To thrive in this role, you should have: Must Have - Domain knowledge in Corporate Payments and … familiarity with related areas such as Accounting Services and Liquidity Management. Proficiency in API Design, microservices, and integration platforms. Experience with Cloud Platforms (AWS, Azure, GCP). Knowledge of DevOps, CI/CD pipelines, and containerization (Docker, Kubernetes). A strong foundation in both Waterfall and Agile SDLC methodologies. Excellent coordination and communication skills to engage with business More ❯
Employment Type: Contract
Rate: £750/day
Posted:

Solution Architect (Chester)

Chester, Cheshire, United Kingdom
Hybrid / WFH Options
Pontoon
systems/subsystems and their interfaces while defining non-functional requirements. Collaborate with stakeholders and vendors to ensure solutions are fit for purpose and evaluate the impact of strategic design decisions. Lead the rapid shaping of high-level architecture while maintaining flexibility and modularity. Utilize best practices and templates to create comprehensive architectural designs. Work closely with Product Managers … to prioritize technology-focused backlog items. Clarify architecture for development teams and provide solution options for any challenges. Conduct design reviews to ensure all non-functional requirements are met, focusing on aspects such as security, performance, and scalability. What We're Looking For: To thrive in this role, you should have: Must Have - Domain knowledge in Corporate Payments and … familiarity with related areas such as Accounting Services and Liquidity Management. Proficiency in API Design, microservices, and integration platforms. Experience with Cloud Platforms (AWS, Azure, GCP). Knowledge of DevOps, CI/CD pipelines, and containerization (Docker, Kubernetes). A strong foundation in both Waterfall and Agile SDLC methodologies. Excellent coordination and communication skills to engage with business More ❯
Employment Type: Contract
Rate: £750/day
Posted:

Solution Architect

Bromley, Kent, England, United Kingdom
Hybrid / WFH Options
Pontoon
systems/subsystems and their interfaces while defining non-functional requirements. Collaborate with stakeholders and vendors to ensure solutions are fit for purpose and evaluate the impact of strategic design decisions. Lead the rapid shaping of high-level architecture while maintaining flexibility and modularity. Utilize best practices and templates to create comprehensive architectural designs. Work closely with Product Managers … to prioritize technology-focused backlog items. Clarify architecture for development teams and provide solution options for any challenges. Conduct design reviews to ensure all non-functional requirements are met, focusing on aspects such as security, performance, and scalability. What We're Looking For:To thrive in this role, you should have: Must Have - Domain knowledge in Corporate Payments and … familiarity with related areas such as Accounting Services and Liquidity Management. Proficiency in API Design, microservices, and integration platforms. Experience with Cloud Platforms (AWS, Azure, GCP). Knowledge of DevOps, CI/CD pipelines, and containerization (Docker, Kubernetes). A strong foundation in both Waterfall and Agile SDLC methodologies. Excellent coordination and communication skills to engage with business More ❯
Employment Type: Contractor
Rate: £750 per day
Posted:

Solutions Architect - Corporate Payments

London, United Kingdom
Adecco
adapt to evolving requirements Collaborate with stakeholders, vendors, and development teams Ensure non-functional requirements are met (e.g. security, scalability, performance) Support agile delivery and architectural runway planning Lead design reviews and resolve technical impediments Required Skills: Deep domain expertise in Corporate Payments (essential) and related financial services Strong experience in API design , microservices , and integration platforms More ❯
Employment Type: Contract
Posted:

Solutions Architect - Corporate Payments

London, South East, England, United Kingdom
Adecco
adapt to evolving requirements Collaborate with stakeholders, vendors, and development teams Ensure non-functional requirements are met (e.g. security, scalability, performance) Support agile delivery and architectural runway planning Lead design reviews and resolve technical impediments Required Skills: Deep domain expertise in Corporate Payments (essential) and related financial services Strong experience in API design , microservices , and integration platforms More ❯
Employment Type: Contractor
Rate: Salary negotiable
Posted:

AI Engineer Front End

City of London, London, United Kingdom
Adecco
in a greenfield, lab-first environment to prototype, iterate, and deploy solutions that meet the highest standards of performance, security, and compliance in a regulated financial setting. Accountabilities & Responsibilities Design and develop modern, responsive front-end applications from the ground up using React, TypeScript, and Next.js. Build secure, performant user interfaces that integrate with LLM APIs (e.g., Gemini, Azure … systems. Implement advanced front-end security features including token handling, session management, data masking, and audit logging. Translate UX/UI designs into modular, reusable components aligned with enterprise design systems. Integrate front-end applications with REST/GraphQL APIs, WebSockets, and backend services. Collaborate with AI engineers, backend developers, and cloud architects to deliver end-to-end solutions. … regular code reviews. Deploy applications to GCP (Firebase, Cloud Run) and Azure App Services using CI/CD pipelines hardened for security and compliance. Participate in code reviews, technical design discussions, and architecture planning sessions. Required Knowledge, Skills & Experience Proven experience building secure, production-grade front-end applications in regulated environments (e.g., finance, healthcare, government). Strong proficiency in More ❯
Employment Type: Contract
Posted:

AI Engineer Front End

London, South East, England, United Kingdom
Adecco
in a greenfield, lab-first environment to prototype, iterate, and deploy solutions that meet the highest standards of performance, security, and compliance in a regulated financial setting. Accountabilities & Responsibilities Design and develop modern, responsive front-end applications from the ground up using React, TypeScript, and Next.js. Build secure, performant user interfaces that integrate with LLM APIs (e.g., Gemini, Azure … systems. Implement advanced front-end security features including token handling, session management, data masking, and audit logging. Translate UX/UI designs into modular, reusable components aligned with enterprise design systems. Integrate front-end applications with REST/GraphQL APIs, WebSockets, and backend services. Collaborate with AI engineers, backend developers, and cloud architects to deliver end-to-end solutions. … regular code reviews. Deploy applications to GCP (Firebase, Cloud Run) and Azure App Services using CI/CD pipelines hardened for security and compliance. Participate in code reviews, technical design discussions, and architecture planning sessions. Required Knowledge, Skills & Experience Proven experience building secure, production-grade front-end applications in regulated environments (e.g., finance, healthcare, government). Strong proficiency in More ❯
Employment Type: Contractor
Rate: Salary negotiable
Posted:

Full Stack Developer

United Kingdom
Hybrid / WFH Options
ea Consulting Group Ltd
Strong backend expertise with Python (FastAPI preferred) Proven experience with Azure cloud deployment & management Proficiency in Vue3 and modern frontend development practices Solid knowledge of MongoDB, data modeling, and API design Experience with CI/CD, containerization, and DevOps practices Excellent problem-solving and collaboration skills ?? Nice to Have Experience with GenAI integrations (AWS Bedrock, LLMs, RAG, vector More ❯
Employment Type: Contract, Work From Home
Rate: £250 - £275 per day
Posted:

Java Developer

Farnborough, Hampshire, England, United Kingdom
FDM Group
and scalable application development. This role is ideal for professionals who thrive in agile settings and are eager to continuously learn and evolve with the latest technology trends. Responsibilities Design, develop, and maintain scalable applications using Java, Spring, and Spring Boot Develop and manage RESTful APIs for seamless system integrations Collaborate with DevOps teams to build and optimize CI … IntelliJ IDEA Monitor, log, and troubleshoot applications using Splunk and log4j Participate in all Agile ceremonies, including sprint planning, daily stand-ups, reviews, and retrospectives Contribute to technical solution design by identifying development challenges and proposing effective strategies Ensure secure coding practices, including secrets management with tools such as HashiCorp Vault Work collaboratively across departments to ensure alignment with … hands-on experience in Spring and Spring Boot frameworks Experience in continuous integration and deployment tools, including Jenkins, Ansible, SonarQube, and Nexus Solid understanding of RESTful web services and API design principles Knowledge and practical use of secure development tools, particularly Vault Proficient in using GitHub for version control and IntelliJ IDEA as a development environment Familiarity with More ❯
Employment Type: Contractor
Rate: £50,000 per annum
Posted:

Senior Developer

Bristol, Avon, South West, United Kingdom
Hybrid / WFH Options
Oscar Associates (UK) Limited
is currently around 60% complete, and you'll be responsible for leading the technical delivery of the remaining 40% to launch You'll be joining an experienced product and design team, working closely with stakeholders and end users and must be able to engage with end users in a clear,non technical manner to ensure smooth delivery . If … Responsibilities Lead development of the remaining platform features to completion. Work across front-end (React, TypeScript, Next.js) and back-end (Java, Node.js, Supabase, Postgres) . Responsible for backend architecture, API design, and integration strategy. Implement serverless functions using AWS Lambda for backend microservices. Work with AWS EventBridge, SQS, SES, SNS for messaging and event-driven workflows. Bug fixes More ❯
Employment Type: Contract, Work From Home
Rate: £550 - £600 per day
Posted:

Integration Engineer Contact (Outside IR35) - Oxfordshire

Oxford, Oxfordshire, South East, United Kingdom
Halian Technology Limited
Strong documentation and communication - Ability to work with business stakeholders (e.g., Marketing, Ops) - Project management or agile familiarity - Problem-solving and debugging - Security awareness (especially around data flows and API access) - Testing and Quality Assurance Tech RESTful API design and integration Power Automate (workflow automation) Power Apps (low-code app development) SQL (data querying and transformation API More ❯
Employment Type: Contract
Rate: From £400 to £550 per day
Posted:

FullStack Software Engineer

City of London, London, United Kingdom
Mentmore Recruitment
Experience working closely with product teams and designing for real users Strong frontend skills (JavaScript/Typescript, React/Angular, HTML) and backend expertise (Node.js, Python) Proven experience in API design and system integration Proficiency with Microsoft Azure and familiarity with databases, IAM, containers, and deployment tools Comfortable with rapid prototyping tools (e.g., Figma) Solid understanding of the … platforms Support low-code solutions, especially within Power Platform Agile & Iterative Development Work within a modern agile framework Participate in backlog grooming, technical scoping, and story writing Engage in design sessions, code reviews, and retrospectives Security, Quality & Operations Ensure compliance with security, privacy, and operational standards Monitor and improve the health of production code Enhance testing and deployment pipelines More ❯
Employment Type: Contract
Rate: £70000 - £80000/annum
Posted:

Full Stack Developer [CONTRACT - outsisde IR35

Cambridge, Cambridgeshire, United Kingdom
SoCode Limited
Responsible for the creation and development of software, including but not limited to: All aspects of the full software development life cycle, including requirements analysis, design, development, testing, documentation and training. Deliver robust, clean, high quality full stack applications. Creation of functional designs and specifications. Rigorous approach to testing, including writing unit and integration tests. Support the creation of … required quality standards. Experience and Qualifications Required Experience in full stack development. Experience in frontend development with React and Next.js. Experience in backend development with Node.js. Experience in database design with PostgreSQL. Strong architectural skills and understanding of RESTful API design. Good analytical and problem-solving ability. Attention to detail and a passion for producing high quality software More ❯
Employment Type: Contract
Rate: £300 - £400/day
Posted:

Solutions Architects - MS Technologies, SolarWinds, ServiceNow

London, United Kingdom
Hybrid / WFH Options
CBSbutler Holdings Limited trading as CBSbutler
work history as an MS Solutions Architect + Experience with SolarWinds & ServiceNow highly desirable Overview We're looking for 2 Solution Architects to join a major customer engagement, providing design and assurance across multiple technology workstreams. This is a hands-on role where you'll bring technical depth, architectural oversight, and the ability to challenge and shape solutions that … deliver lasting value. Key Responsibilities Lead design and assurance activities across cloud and on-premise environments. Work closely with stakeholders to define solution architectures that align with business objectives. Provide technical governance and assurance across project delivery. Evaluate and recommend technologies, ensuring scalable, secure, and cost-effective designs. Collaborate with engineering teams to ensure solutions are implemented to specification. … Produce high-quality architectural documentation, design patterns, and roadmaps. Core Skills & Experience Proven background as a Solution Architect within enterprise-scale environments. Strong expertise in Microsoft technologies (cloud and on-premise). Experience in hybrid cloud architectures (Azure preferred). Knowledge of infrastructure monitoring (e.g., SolarWinds). Familiarity with ITSM platforms such as ServiceNow. Strong stakeholder management and communication More ❯
Employment Type: Contract
Rate: £550 - £620/day
Posted:
API Design
10th Percentile
£363
25th Percentile
£425
Median
£525
75th Percentile
£663
90th Percentile
£750