Date posted
Commute time
Locations
Type of Company
Job types
Salaries
Locations
Locations
Salaries
Date posted
Type of Company
Job types
36 Contract API jobs in Westminster + 20 miles
144 exact matches jobs are outside your preferred location
)
This role involves architecting cloud-native solutions using Azure Cosmos DB (SQL API and Mongo API), implementing effective partitioning strategies, indexing, and consistency models to support real-time financial data processing. * Architect and develop cloud-native applications using Azure Cosmos DB (SQL API, Mongo API)
This role involves architecting cloud-native solutions using Azure Cosmos DB (SQL API and Mongo API), implementing effective partitioning strategies, indexing, and consistency models to support real-time financial data processing. * Architect and develop cloud-native applications using Azure Cosmos DB (SQL API, Mongo API)
NEW
)
Maintain and troubleshoot the custom C# .NET backend API used as a wrapper for Contentful CMS. * API Gateway * Solid expertise in C# .NET, particularly in API development and integration. * Familiarity with Contentful CMS and API integration.
Maintain and troubleshoot the custom C# .NET backend API used as a wrapper for Contentful CMS. * API Gateway * Solid expertise in C# .NET, particularly in API development and integration. * Familiarity with Contentful CMS and API integration.
NEW
)
Strong application security knowledge (OWASP Top 10, API security).
Strong application security knowledge (OWASP Top 10, API security).
NEW
Strong application security knowledge (OWASP Top 10, API security).
Strong application security knowledge (OWASP Top 10, API security).
NEW
)
Lead .Net Software Developer
Lead .Net Software Developer
Hireful
Milton Keynes, Buckinghamshire
£65k - £75k base salary plus Bonus and awesome 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
NEWFEATURED
)
Strong application security background (OWASP Top 10, API security).
Strong application security background (OWASP Top 10, API security).
NEW
Contribute to backend/API testing and support security testing initiatives. * Strong knowledge of API testing and backend validation.
Contribute to backend/API testing and support security testing initiatives. * Strong knowledge of API testing and backend validation.
NEW
Job Title: Solution Architect - Location: Windsor, UK - Work Model: Hybrid (1 day per week in office) Job Type: Contract (Inside IR35) Duration: 6 Months - We are seeking an experienced Solution Architect to join our team in Windsor. You will play a key role in defining, communicating, and implementing strategic technology standards and roadmaps, ensuring robust and scalable solutions for business transformation initiatives. This is a hybrid role requiring one day per week in the office. * Identify, publish, and communicate strategic technology standards, frameworks, principles, and roadmaps to guide technology decisions and leverage efficiency opportunities. * Analyze the impact of implementing new technologies into the IT infrastructure. * Assist Solution Architects, Product Specialists, and Project Managers in matching technology services to specific business servi
Job Title: Solution Architect - Location: Windsor, UK - Work Model: Hybrid (1 day per week in office) Job Type: Contract (Inside IR35) Duration: 6 Months - We are seeking an experienced Solution Architect to join our team in Windsor. You will play a key role in defining, communicating, and implementing strategic technology standards and roadmaps, ensuring robust and scalable solutions for business transformation initiatives. This is a hybrid role requiring one day per week in the office. * Identify, publish, and communicate strategic technology standards, frameworks, principles, and roadmaps to guide technology decisions and leverage efficiency opportunities. * Analyze the impact of implementing new technologies into the IT infrastructure. * Assist Solution Architects, Product Specialists, and Project Managers in matching technology services to specific business servi
NEW
)
Senior Infrastructure Operations Engineer - SC Cleared
Senior Infrastructure Operations Engineer - SC Cleared
Certes IT Service Solutions
London
£540 - £550 per day + Negotiable
Integration: Experience with Graph API, Logic Apps, and automation runbooks for cross-platform orchestration.
Integration: Experience with Graph API, Logic Apps, and automation runbooks for cross-platform orchestration.
NEW
)
.NET Framework Version 4.5 or above including strong WCF\ Web API experience
.NET Framework Version 4.5 or above including strong WCF\ Web API experience
NEW
)
.NET Framework Version 4.5 or above including strong WCF\ Web API experience
.NET Framework Version 4.5 or above including strong WCF\ Web API experience
NEW
)
Understanding of cloud-based solutions and communication protocols (SOAP, API, HTTPS, SFTP, etc.).
Understanding of cloud-based solutions and communication protocols (SOAP, API, HTTPS, SFTP, etc.).
NEW
)
As a Digital Product Owner youll work with a Senior Product Manager to continually improve Heathrows digital proposition, which could include product ownership of the newly introduced My Heathrow platform and commercial B2B API portal. * Deliver innovative digital experiences to a global audience to improve conversion, revenue and third-party developers using the commercial B2B API portal. * API product experience will be a further advantage.
As a Digital Product Owner youll work with a Senior Product Manager to continually improve Heathrows digital proposition, which could include product ownership of the newly introduced My Heathrow platform and commercial B2B API portal. * Deliver innovative digital experiences to a global audience to improve conversion, revenue and third-party developers using the commercial B2B API portal. * API product experience will be a further advantage.
NEW
)
We are looking for a Software Engineer with a strong foundation in API development and C# to join our data engineering team in a highly regulated industry. Were seeking candidates with over 5 years of relevant experience, a solid understanding of software system design, and a strong command of C# and modern API development patterns. Experience with authentication, authorization, and secure API communication (OAuth2, JWT, etc.). Familiarity with API gateways, microservice architecture, and asynchronous messaging patterns (e.g., queues, event buses).
We are looking for a Software Engineer with a strong foundation in API development and C# to join our data engineering team in a highly regulated industry. Were seeking candidates with over 5 years of relevant experience, a solid understanding of software system design, and a strong command of C# and modern API development patterns. Experience with authentication, authorization, and secure API communication (OAuth2, JWT, etc.). Familiarity with API gateways, microservice architecture, and asynchronous messaging patterns (e.g., queues, event buses).
NEWPREMIUM
)
Developer, .NET, C#, AI Code, Remote, COR7355
Developer, .NET, C#, AI Code, Remote, COR7355
Corriculo Ltd
Oxford, Oxfordshire
£40k - 50k per year + Remote Working
A Developer with experience in .NET, C#, and JavaScript is urgently required to join a dynamic and innovative team in a leading organisation working on a fully remote basis. This is an excellent opportunity to contribute to technological developments, streamline processes, and enhance operational efficiency. The Role - As a Developer, you will work closely with the Senior Developer to design and implement internal tools and solutions. Collaborating with various departments, you’ll support development-related queries and build integrations with third-party platforms via APIs. This role is central to improving workflows, enabling innovative practices, and contributing to the company’s technology strategy. The Company - Our client is a forward-thinking organisation committed to technological advancement and efficiency.
A Developer with experience in .NET, C#, and JavaScript is urgently required to join a dynamic and innovative team in a leading organisation working on a fully remote basis. This is an excellent opportunity to contribute to technological developments, streamline processes, and enhance operational efficiency. The Role - As a Developer, you will work closely with the Senior Developer to design and implement internal tools and solutions. Collaborating with various departments, you’ll support development-related queries and build integrations with third-party platforms via APIs. This role is central to improving workflows, enabling innovative practices, and contributing to the company’s technology strategy. The Company - Our client is a forward-thinking organisation committed to technological advancement and efficiency.
NEW
Job title: Lead Integration Developer - Location: London, UK - Job type: Contract (Inside IR35) About the Role As a Lead Integration Developer, you will be responsible for designing, developing, and maintaining integration solutions across various platforms, including Guidewire InsuranceSuite and other core systems. You will lead a team of developers, collaborate with stakeholders, and ensure the delivery of integration projects that meet business and technical requirements. What will you do? * Lead the design and implementation of integration solutions using APIs, web services, and messaging systems. * Collaborate with business analysts and architects to define integration requirements and strategies. * Develop and maintain integration components using technologies such as Java, REST/JSON, XML, and Enterprise Messaging Systems.
Job title: Lead Integration Developer - Location: London, UK - Job type: Contract (Inside IR35) About the Role As a Lead Integration Developer, you will be responsible for designing, developing, and maintaining integration solutions across various platforms, including Guidewire InsuranceSuite and other core systems. You will lead a team of developers, collaborate with stakeholders, and ensure the delivery of integration projects that meet business and technical requirements. What will you do? * Lead the design and implementation of integration solutions using APIs, web services, and messaging systems. * Collaborate with business analysts and architects to define integration requirements and strategies. * Develop and maintain integration components using technologies such as Java, REST/JSON, XML, and Enterprise Messaging Systems.
NEW
)
Senior Data Architect
Senior Data Architect
Cambridge University Press & Assessment
CB2, Cambridge, CB2 8BS
From £70,400 to £94,100 per annum
Job Title:Senior Data Architect - Salary:£70,400 - £94,100 - Location:Cambridge/Hybrid with office attendance for an average of 2 days a week - Contract:Permanent - Shape the future of data and AI at Cambridge University Press & Assessment - We are Cambridge University Press & Assessment, a world-leading academic publisher and assessment organisation and a proud part of the University of Cambridge. About the role - As a SeniorData Architect, you will play a pivotal role in delivering a coherent and scalable data framework aligned with our enterprise data strategy. You'll advance key architectural principles such as data mesh, data products, and data contracts, while enabling the strategic use of Artificial Intelligence (AI) and Generative AI (GenAI) across the organisation. You'll beresponsible for promoting the data strategy, securing stakeholder buy-in, and defining
Job Title:Senior Data Architect - Salary:£70,400 - £94,100 - Location:Cambridge/Hybrid with office attendance for an average of 2 days a week - Contract:Permanent - Shape the future of data and AI at Cambridge University Press & Assessment - We are Cambridge University Press & Assessment, a world-leading academic publisher and assessment organisation and a proud part of the University of Cambridge. About the role - As a SeniorData Architect, you will play a pivotal role in delivering a coherent and scalable data framework aligned with our enterprise data strategy. You'll advance key architectural principles such as data mesh, data products, and data contracts, while enabling the strategic use of Artificial Intelligence (AI) and Generative AI (GenAI) across the organisation. You'll beresponsible for promoting the data strategy, securing stakeholder buy-in, and defining
NEWFEATURED
AVEVA is creating software trusted by over 90% of leading industrial companies. Job Title: Senior Software Developer - Location: Cambridge, United Kingdom Hybrid (3 days at the office) Employment Type: Full-time regular (flexible working options available) The job - As part of our Industrial Platform Group, you will join a talented team of software engineers dedicated to designing, developing, and evolving CONNECT - the core industrial intelligence platform at AVEVA. CONNECT powers a diverse range of digital solutions deployed across global industries by AVEVA and our partners. In this role, youll work closely with internal stakeholders and engineering teams to understand requirements, shape system architecture, and deliver scalable platform capabilities. Your contributions will directly impact how CONNECT supports our customers digital transformation journeys and ens
AVEVA is creating software trusted by over 90% of leading industrial companies. Job Title: Senior Software Developer - Location: Cambridge, United Kingdom Hybrid (3 days at the office) Employment Type: Full-time regular (flexible working options available) The job - As part of our Industrial Platform Group, you will join a talented team of software engineers dedicated to designing, developing, and evolving CONNECT - the core industrial intelligence platform at AVEVA. CONNECT powers a diverse range of digital solutions deployed across global industries by AVEVA and our partners. In this role, youll work closely with internal stakeholders and engineering teams to understand requirements, shape system architecture, and deliver scalable platform capabilities. Your contributions will directly impact how CONNECT supports our customers digital transformation journeys and ens
NEW
)
Position: AI Engineer / AI Agent / Backend AI Engineer - Location: Remote - Work Type: Contract - We're looking for an AI Engineer to design and deliver scalable AI/ML systems and agentic applications. You'll work on LLMs, RAG pipelines, model deployment, and cloud-native solutions that drive real-world impact. * Strong coding skills in Java / TypeScript /Python * Experience with LLMs, NLP, and ML frameworks (Hugging Face, PyTorch, TensorFlow, LangChain) * Cloud & DevOps expertise (AWS/Azure, Docker, Kubernetes, CI/CD pipelines) * Knowledge of microservices, APIs, distributed systems - Why join us? * Work on cutting-edge AI innovation * Collaborative, cross-functional environment * Competitive salary + growth opportunities - We encourage you to apply or send me your updated resume to nandiraju . b @ randstad . co. uk
Position: AI Engineer / AI Agent / Backend AI Engineer - Location: Remote - Work Type: Contract - We're looking for an AI Engineer to design and deliver scalable AI/ML systems and agentic applications. You'll work on LLMs, RAG pipelines, model deployment, and cloud-native solutions that drive real-world impact. * Strong coding skills in Java / TypeScript /Python * Experience with LLMs, NLP, and ML frameworks (Hugging Face, PyTorch, TensorFlow, LangChain) * Cloud & DevOps expertise (AWS/Azure, Docker, Kubernetes, CI/CD pipelines) * Knowledge of microservices, APIs, distributed systems - Why join us? * Work on cutting-edge AI innovation * Collaborative, cross-functional environment * Competitive salary + growth opportunities - We encourage you to apply or send me your updated resume to nandiraju . b @ randstad . co. uk
NEWFEATURED
)
we are hiring forTechnical Data Architect - location: Central London - Type : Permanent - Hybrid role (2-3 days from client location) We are seeking a highly skilled TechnicalData Architect- with expertise in Databricks, PySpark, and modern data engineering practices. The ideal candidate will lead the design, development, and optimization of scalable data pipelines, while ensuring data accuracy, consistency, and performance across the enterprise Lakehouse platform. This role requires strong leadership, technical depth, and the ability to collaborate with cross-functional teams. Key Responsibilities - Lead the design, development, and maintenance of scalable, high-performance data pipelines on Databricks. Architect and implement data ingestion, transformation, and integration workflows using PySpark, SQL, and Delta Lake.
we are hiring forTechnical Data Architect - location: Central London - Type : Permanent - Hybrid role (2-3 days from client location) We are seeking a highly skilled TechnicalData Architect- with expertise in Databricks, PySpark, and modern data engineering practices. The ideal candidate will lead the design, development, and optimization of scalable data pipelines, while ensuring data accuracy, consistency, and performance across the enterprise Lakehouse platform. This role requires strong leadership, technical depth, and the ability to collaborate with cross-functional teams. Key Responsibilities - Lead the design, development, and maintenance of scalable, high-performance data pipelines on Databricks. Architect and implement data ingestion, transformation, and integration workflows using PySpark, SQL, and Delta Lake.
NEWFEATURED
)
Up to £640 per day (Inside IR35) London / Remote - 6 months - My client is an instantly recognisable consultancy who urgently requires a Lead Full Stack Developer to join a business-critical programme. * Proven experience working as a Lead Java Developer within the public sector * Active Security Clearance (SC) * Java (8/11/17+): Expert-level programming and deep understanding of the language and its core libraries * Spring Boot: Expert in building RESTful APIs and microservices * AWS: Strong experience with core AWS services (EC2, S3, Lambda, IAM, etc.) * Kafka / Messaging Systems: Expertise in building event-driven architectures * SQL: Strong experience with relational databases and query optimization * REST / JSON APIs: Designing, developing, and consuming scalable APIs * Docker: Proficiency in containerizing applications for local and cloud environments
Up to £640 per day (Inside IR35) London / Remote - 6 months - My client is an instantly recognisable consultancy who urgently requires a Lead Full Stack Developer to join a business-critical programme. * Proven experience working as a Lead Java Developer within the public sector * Active Security Clearance (SC) * Java (8/11/17+): Expert-level programming and deep understanding of the language and its core libraries * Spring Boot: Expert in building RESTful APIs and microservices * AWS: Strong experience with core AWS services (EC2, S3, Lambda, IAM, etc.) * Kafka / Messaging Systems: Expertise in building event-driven architectures * SQL: Strong experience with relational databases and query optimization * REST / JSON APIs: Designing, developing, and consuming scalable APIs * Docker: Proficiency in containerizing applications for local and cloud environments
NEW
Position: Backend Engineer - Location: Remote (UK) Work Type: Contract - Join our team to build the backbone of a global music streaming platform! We're looking for a JAVA Backend Engineer who loves coding, solving problems, and delivering features that reach millions of users. * Build scalable Java & SpringBoot microservices. * Develop APIs and backend tools for engineers across the company. * Use TDD, CI/CD, Docker, Kubernetes, Jenkins, and GCP services. * Work with alternate languages like Python, Scala, Golang, or Node.js for backend tasks. * Collaborate in an Agile environment with cross-functional teams. * Strong backend development skills (Java and microservices). * Experience with microservices, TDD, CI/CD, Docker & Kubernetes, and cloud platforms (GCP preferred). * Familiarity with and one of Python, Golang, Scala or Node.js is a plus.
Position: Backend Engineer - Location: Remote (UK) Work Type: Contract - Join our team to build the backbone of a global music streaming platform! We're looking for a JAVA Backend Engineer who loves coding, solving problems, and delivering features that reach millions of users. * Build scalable Java & SpringBoot microservices. * Develop APIs and backend tools for engineers across the company. * Use TDD, CI/CD, Docker, Kubernetes, Jenkins, and GCP services. * Work with alternate languages like Python, Scala, Golang, or Node.js for backend tasks. * Collaborate in an Agile environment with cross-functional teams. * Strong backend development skills (Java and microservices). * Experience with microservices, TDD, CI/CD, Docker & Kubernetes, and cloud platforms (GCP preferred). * Familiarity with and one of Python, Golang, Scala or Node.js is a plus.
NEWFEATURED
)
Location: Hybrid Working London Office/Remote - Reporting to: Engineering Manager - We are seeking innovative Linux Systems Engineer to help shape the next generation of secure endpoint solutions. This role is open to both experienced engineers ready to tackle complex challenges and mid-level engineers eager to learn, grow, and innovate. You will work at the intersection of Linux internals, networking, virtualisation, and security, building solutions for high-profile clients. The work you do will contribute to endpoint technologies that will set the direction for the next decadejust as todays established solutions set the standard a decade ago. * Linux OS Development: Design, develop, and maintain Linux-based operating systems with a strong emphasis on security, performance, and reliability. * System & Security Engineering: Work with Linux distributions, kernel-level
Location: Hybrid Working London Office/Remote - Reporting to: Engineering Manager - We are seeking innovative Linux Systems Engineer to help shape the next generation of secure endpoint solutions. This role is open to both experienced engineers ready to tackle complex challenges and mid-level engineers eager to learn, grow, and innovate. You will work at the intersection of Linux internals, networking, virtualisation, and security, building solutions for high-profile clients. The work you do will contribute to endpoint technologies that will set the direction for the next decadejust as todays established solutions set the standard a decade ago. * Linux OS Development: Design, develop, and maintain Linux-based operating systems with a strong emphasis on security, performance, and reliability. * System & Security Engineering: Work with Linux distributions, kernel-level
NEW
)
*outside iR35* What You'll Be Doing * Designing and developing enterprise-grade solutions in an Agile team. * Building and maintaining middleware services using C#, REST APIs, FIX messaging, XML, and Microservices. * Leading architecture discussions, code reviews, and release management. * Collaborating with users and cross-functional teams to define and execute testing strategies. * Mentoring junior developers and contributing to internal best practices. What You Bring * A strong academic background in Computer Science, Engineering, or a related field. * Proven experience in commodities trading, especially with derivatives and platforms like ICE, CME, NASDAQ, Trayport, or TT. * Deep knowledge of C# .NET, RESTful services, and microservice architecture. * Hands-on experience with FIX messaging, XML, AMQ, and ideally nHibernate, OData, and TDD.
*outside iR35* What You'll Be Doing * Designing and developing enterprise-grade solutions in an Agile team. * Building and maintaining middleware services using C#, REST APIs, FIX messaging, XML, and Microservices. * Leading architecture discussions, code reviews, and release management. * Collaborating with users and cross-functional teams to define and execute testing strategies. * Mentoring junior developers and contributing to internal best practices. What You Bring * A strong academic background in Computer Science, Engineering, or a related field. * Proven experience in commodities trading, especially with derivatives and platforms like ICE, CME, NASDAQ, Trayport, or TT. * Deep knowledge of C# .NET, RESTful services, and microservice architecture. * Hands-on experience with FIX messaging, XML, AMQ, and ideally nHibernate, OData, and TDD.
NEW
)
*outside iR35* What You'll Be Doing * Designing and developing enterprise-grade solutions in an Agile team. * Building and maintaining middleware services using C#, REST APIs, FIX messaging, XML, and Microservices. * Leading architecture discussions, code reviews, and release management. * Collaborating with users and cross-functional teams to define and execute testing strategies. * Mentoring junior developers and contributing to internal best practices. What You Bring * A strong academic background in Computer Science, Engineering, or a related field. * Proven experience in commodities trading, especially with derivatives and platforms like ICE, CME, NASDAQ, Trayport, or TT. * Deep knowledge of C# .NET, RESTful services, and microservice architecture. * Hands-on experience with FIX messaging, XML, AMQ, and ideally nHibernate, OData, and TDD.
*outside iR35* What You'll Be Doing * Designing and developing enterprise-grade solutions in an Agile team. * Building and maintaining middleware services using C#, REST APIs, FIX messaging, XML, and Microservices. * Leading architecture discussions, code reviews, and release management. * Collaborating with users and cross-functional teams to define and execute testing strategies. * Mentoring junior developers and contributing to internal best practices. What You Bring * A strong academic background in Computer Science, Engineering, or a related field. * Proven experience in commodities trading, especially with derivatives and platforms like ICE, CME, NASDAQ, Trayport, or TT. * Deep knowledge of C# .NET, RESTful services, and microservice architecture. * Hands-on experience with FIX messaging, XML, AMQ, and ideally nHibernate, OData, and TDD.
NEW