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70 API jobs in Croxley Green + 20 miles
235 exact matches jobs are outside your preferred location
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Our Purpose - Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, were helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential. Title and Summary - Overview - We are looking for a software engineer to join an award winning team with a proven track record of combining data science techniques with an intimate knowledge of payments data to aid Financial Institutions in their fight against money laundering and fraud. Headquartered in The City of London, we craft bespoke services that help our clien
Our Purpose - Mastercard powers economies and empowers people in 200+ countries and territories worldwide. Together with our customers, were helping build a sustainable economy where everyone can prosper. We support a wide range of digital payments choices, making transactions secure, simple, smart and accessible. Our technology and innovation, partnerships and networks combine to deliver a unique set of products and services that help people, businesses and governments realize their greatest potential. Title and Summary - Overview - We are looking for a software engineer to join an award winning team with a proven track record of combining data science techniques with an intimate knowledge of payments data to aid Financial Institutions in their fight against money laundering and fraud. Headquartered in The City of London, we craft bespoke services that help our clien
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Data Services Team Lead / Manager - Location: Epsom - Salary: Competitive - Team: 4 direct reports, with opportunity to grow * Hybrid working (2 days office / 3 days remote) * Private medical cover * Excellent pension contributions and bonus scheme * Car scheme for employees & family wellbeing support * 25+ days holiday plus volunteering leave * Onsite gym & other great facilities * Flexible working and extensive training options - We're looking for a driven, hands-on Data Services Team Lead / Manager to guide a team of data engineers, oversee daily operations and deliver high-quality data solutions for a well-established local client. The ideal individual is someone who enjoys being technical whilst also inspiring and developing their team. This role would also be a great opportunity for a Data Engineer who has led projects and is ready to step into a leadership posi
Data Services Team Lead / Manager - Location: Epsom - Salary: Competitive - Team: 4 direct reports, with opportunity to grow * Hybrid working (2 days office / 3 days remote) * Private medical cover * Excellent pension contributions and bonus scheme * Car scheme for employees & family wellbeing support * 25+ days holiday plus volunteering leave * Onsite gym & other great facilities * Flexible working and extensive training options - We're looking for a driven, hands-on Data Services Team Lead / Manager to guide a team of data engineers, oversee daily operations and deliver high-quality data solutions for a well-established local client. The ideal individual is someone who enjoys being technical whilst also inspiring and developing their team. This role would also be a great opportunity for a Data Engineer who has led projects and is ready to step into a leadership posi
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Date Posted: 05/12/2025 - Location: London - Job Type: Full time - London Hybrid (minimum 50% office based) Who are Just? We help people achieve a better later life. Thats our purpose and its the reason we exist. We are a fast-growing FTSE 250 company helping customers enjoy the retirement they deserve. We do this through a variety of market leading, award-winning products and services, delivered by a diverse team of over 1,400 purpose-led colleagues who genuinely put the customer at the heart of everything we do. This is a brilliant time to join our business. We are on an exciting growth journey to become the UKs most loved retirement expert. About the Role - We are leading a bold and transformative journey - and were looking for a Product Owner to join our flagship technology system transformation programme within our Retail B2B2C business.
Date Posted: 05/12/2025 - Location: London - Job Type: Full time - London Hybrid (minimum 50% office based) Who are Just? We help people achieve a better later life. Thats our purpose and its the reason we exist. We are a fast-growing FTSE 250 company helping customers enjoy the retirement they deserve. We do this through a variety of market leading, award-winning products and services, delivered by a diverse team of over 1,400 purpose-led colleagues who genuinely put the customer at the heart of everything we do. This is a brilliant time to join our business. We are on an exciting growth journey to become the UKs most loved retirement expert. About the Role - We are leading a bold and transformative journey - and were looking for a Product Owner to join our flagship technology system transformation programme within our Retail B2B2C business.
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Staff Software Engineer Robotics & Life Sciences Automation - Location: London, UK - Hybrid (3 days/week on site) Contract: 4 months with possibility of extension - Start: ASAP (Dec 2025 / Jan 2026) Automata: accelerating breakthroughs that save lives - Automata builds automation that accelerates life sciences: enabling faster drug discovery, next-generation personalised medicines, and high-precision diagnostics where turnaround time can mean the difference between life and death. We believe the future of biology depends on automation that is reliable, scalable and accessible and were building the platform that makes that possible. Our modular lab bench and digital automation platform already run mission-critical workflows in leading research organisations. The next evolution of our product will scale globally, unify robotics with reproducible software interfaces, and
Staff Software Engineer Robotics & Life Sciences Automation - Location: London, UK - Hybrid (3 days/week on site) Contract: 4 months with possibility of extension - Start: ASAP (Dec 2025 / Jan 2026) Automata: accelerating breakthroughs that save lives - Automata builds automation that accelerates life sciences: enabling faster drug discovery, next-generation personalised medicines, and high-precision diagnostics where turnaround time can mean the difference between life and death. We believe the future of biology depends on automation that is reliable, scalable and accessible and were building the platform that makes that possible. Our modular lab bench and digital automation platform already run mission-critical workflows in leading research organisations. The next evolution of our product will scale globally, unify robotics with reproducible software interfaces, and
Senior AI Engineer (Full Stack Python, AI, LLMs, LangChain)
Senior AI Engineer (Full Stack Python, AI, LLMs, LangChain)
Transparent Technology
London
£80000 - £140000 per annum + + bens + shares
Senior Software Engineer (AI Focus) - £80,000-£140,000 + Benefits + Shares + Bonus | London, Edinburgh, or Manchester | Hybrid (Up to 3 Days Onsite per Week, usually less) Join one of the UK's most exciting AI consultancies, an official OpenAI Global Partner founded by a leadership team who have already built and sold a multimillion-pound tech business. They're expanding rapidly and looking for Senior AI/ML Software Engineers (Backend or Full Stack) with strong Python skills and a genuine passion for AI /ML, scalable systems, and modern cloud architecture. You don't need to be an AI or LLM expert yet, you'll learn directly from some of the best in the industry. What You'll Be Doing * Design and deploy scalable agentic applications using Python (and ideally JavaScript/TypeScript) * Build and maintain microservices, APIs, and CI/CD pipelines
Senior Software Engineer (AI Focus) - £80,000-£140,000 + Benefits + Shares + Bonus | London, Edinburgh, or Manchester | Hybrid (Up to 3 Days Onsite per Week, usually less) Join one of the UK's most exciting AI consultancies, an official OpenAI Global Partner founded by a leadership team who have already built and sold a multimillion-pound tech business. They're expanding rapidly and looking for Senior AI/ML Software Engineers (Backend or Full Stack) with strong Python skills and a genuine passion for AI /ML, scalable systems, and modern cloud architecture. You don't need to be an AI or LLM expert yet, you'll learn directly from some of the best in the industry. What You'll Be Doing * Design and deploy scalable agentic applications using Python (and ideally JavaScript/TypeScript) * Build and maintain microservices, APIs, and CI/CD pipelines
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Ideas | People | Trust - We’re BDO. An accountancy and business advisory firm, providing the advice and solutions entrepreneurial organisations need to navigate today’s changing world. We work with the companies that are Britain’s economic engine - ambitious, entrepreneurially-spirited and high-growth businesses that fuel the economy - and directly advise the owners and management teams that lead them. We’ll broaden your horizons - To ensure our services and applications are fit for the modern market, our IT team collaborates with every department. They develop, they explore and they implement the new ideas helping us to change the future of accounting, tax and business consulting. But, just as importantly, they maintain the tech that keeps us advancing. By testing and adopting the future of financial technical solutions, they find new and exciting ways to drive us fo
Ideas | People | Trust - We’re BDO. An accountancy and business advisory firm, providing the advice and solutions entrepreneurial organisations need to navigate today’s changing world. We work with the companies that are Britain’s economic engine - ambitious, entrepreneurially-spirited and high-growth businesses that fuel the economy - and directly advise the owners and management teams that lead them. We’ll broaden your horizons - To ensure our services and applications are fit for the modern market, our IT team collaborates with every department. They develop, they explore and they implement the new ideas helping us to change the future of accounting, tax and business consulting. But, just as importantly, they maintain the tech that keeps us advancing. By testing and adopting the future of financial technical solutions, they find new and exciting ways to drive us fo
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Full Stack .Net Developer (Angular v20/.Net 8 Microservices)
Full Stack .Net Developer (Angular v20/.Net 8 Microservices)
Hays
Gatwick (RH6)
£40000 - £55000 per annum + £40-55k + Benefits
Full Stack .Net Developer (Angular v20 and .NET 8 Microservices) Gatwick (2 days per week in office) £40-55k + Benefits. Your new company - This leading financial and consulting business are looking to bolster their engineering team with a Full Stack .Net Developer to join their core team of 16 Devs. You will be working in their state-of-the-art offices near to Gatwick/Crawley and will be required to work 2 days per week in the office. Your new role - This is a full-stack, full software lifecycle role where Devs are encouraged to bring ideas to the table and challenge the status quo. From architecture and development through to deployment you'll play a key role in building cutting-edge solutions by developing .NET microservices and dynamic Angular front-end applications. Working in a collaborative Agile environment, you'll partner with product owners, QA engineers, an
Full Stack .Net Developer (Angular v20 and .NET 8 Microservices) Gatwick (2 days per week in office) £40-55k + Benefits. Your new company - This leading financial and consulting business are looking to bolster their engineering team with a Full Stack .Net Developer to join their core team of 16 Devs. You will be working in their state-of-the-art offices near to Gatwick/Crawley and will be required to work 2 days per week in the office. Your new role - This is a full-stack, full software lifecycle role where Devs are encouraged to bring ideas to the table and challenge the status quo. From architecture and development through to deployment you'll play a key role in building cutting-edge solutions by developing .NET microservices and dynamic Angular front-end applications. Working in a collaborative Agile environment, you'll partner with product owners, QA engineers, an
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A leading retailer are looking for a Senior Android App Developer to join their Mobile Team to contribute to the development and evolution of their Mobile App. As the Senior Android App Developer, you will be responsible for building and maintaining the Android version of the app, ensuring it delivers a pixel-perfect, performant, and luxury-aligned experience for customers. You will be a high-performing developer who thrives on clean architecture, elegant code collaborative delivery whilst working as part of an Agile cross-functional team. Skills and Experience * Strong proficiency in Kotlin and Android SDKs, with a deep understanding of Jetpack libraries, Compose and modern Android architecture components. * Experience with RESTful APIs, JSON, and mobile architecture patterns (MVVM, Clean Architecture).
A leading retailer are looking for a Senior Android App Developer to join their Mobile Team to contribute to the development and evolution of their Mobile App. As the Senior Android App Developer, you will be responsible for building and maintaining the Android version of the app, ensuring it delivers a pixel-perfect, performant, and luxury-aligned experience for customers. You will be a high-performing developer who thrives on clean architecture, elegant code collaborative delivery whilst working as part of an Agile cross-functional team. Skills and Experience * Strong proficiency in Kotlin and Android SDKs, with a deep understanding of Jetpack libraries, Compose and modern Android architecture components. * Experience with RESTful APIs, JSON, and mobile architecture patterns (MVVM, Clean Architecture).
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Software Engineer
Software Engineer
EMBL-EBI
Hinxton, Saffron Walden (CB10), CB10 1SD
From £43,015 to £72,738 per annum based on experience and family
We are looking for a Developer with a strong record in software development and interest in developing AI-based systems for one of the most internationally used data resources in biological science, UniProt. Our team is very dynamic and interdisciplinary, comprising talented and enthusiastic software engineers and bioinformaticians working closely together with biologists and scientists. The UniProt resource is one of the most internationally used resources for protein sequence and functional annotation, providing comprehensive, high-quality, and freely accessible data to a large and diverse research community in genomics, proteins and proteomics. As part of the Computational Annotation team in UniProt, you will be working in the design, development and maintenance of systems that automatically assign high-quality functional annotations to millions of unreviewed prote
We are looking for a Developer with a strong record in software development and interest in developing AI-based systems for one of the most internationally used data resources in biological science, UniProt. Our team is very dynamic and interdisciplinary, comprising talented and enthusiastic software engineers and bioinformaticians working closely together with biologists and scientists. The UniProt resource is one of the most internationally used resources for protein sequence and functional annotation, providing comprehensive, high-quality, and freely accessible data to a large and diverse research community in genomics, proteins and proteomics. As part of the Computational Annotation team in UniProt, you will be working in the design, development and maintenance of systems that automatically assign high-quality functional annotations to millions of unreviewed prote
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Software Engineer
Software Engineer
EMBL-EBI
Hinxton, Saffron Walden (CB10), CB10 1SD
From £43,015 to £72,738 per annum based on experience and family
About the Team - We are looking for a Software engineer with strong record in software development and interested in developing services for one of the most internationally used data resources in biological science, UniProt. Our team is very dynamic and interdisciplinary comprising talented and enthusiastic software engineers and bioinformaticians working closely together with biologists and scientists. The UniProt resource is one of the most internationally used protein databases serving a large and diverse research community in genomics, proteins and proteomics. Duties & Responsibilities - As part of your daily work, you will be designing and developing software and APIs for the UniProt data services and website, providing protein information to the scientific community and computational biologists.
About the Team - We are looking for a Software engineer with strong record in software development and interested in developing services for one of the most internationally used data resources in biological science, UniProt. Our team is very dynamic and interdisciplinary comprising talented and enthusiastic software engineers and bioinformaticians working closely together with biologists and scientists. The UniProt resource is one of the most internationally used protein databases serving a large and diverse research community in genomics, proteins and proteomics. Duties & Responsibilities - As part of your daily work, you will be designing and developing software and APIs for the UniProt data services and website, providing protein information to the scientific community and computational biologists.
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LSEG is seeking a Senior Vulnerability Management Engineer to join our internal offensive security team with focus on driving closure of penetration testing findings. This role bridges offensive security and engineering by translating penetration test results into clear, actionable remediation guidance and partnering with application and platform teams to implement secure fixes. The successful candidate has a strong penetration testing or application security background, hands on remediation experience, and the ability to coordinate multiple collaborators to reduce risk at scale. This is a highly technical, delivery focused role with responsibility for both individual findings and systemic improvements. Key Responsibilities * Analyze and review penetration test reports to understand technical impact, exploitability, and business risk.
LSEG is seeking a Senior Vulnerability Management Engineer to join our internal offensive security team with focus on driving closure of penetration testing findings. This role bridges offensive security and engineering by translating penetration test results into clear, actionable remediation guidance and partnering with application and platform teams to implement secure fixes. The successful candidate has a strong penetration testing or application security background, hands on remediation experience, and the ability to coordinate multiple collaborators to reduce risk at scale. This is a highly technical, delivery focused role with responsibility for both individual findings and systemic improvements. Key Responsibilities * Analyze and review penetration test reports to understand technical impact, exploitability, and business risk.
Looking to hire an Automation Test Engineer, the role spans the automation of low-level business functional tests through to mid-level system integration tests. The successful candidate will have to co-ordinate with Operations Change Business Analysis team, Development teams, and Project managers, as well as testing teams. The successful candidate will have an excellent QA background with experience of a variety of automation test tools, technologies and have business domain expertise and experience of delivery in complex fast moving environments. Excellent communication skills will be vital in this role. The role will report to the Test Manager and work day to day with the Test Lead. Required Skills and Experience * Extensive automation testing experience in Investment Banking IT, preparing and executing automated tests on a Financial platforms.
Looking to hire an Automation Test Engineer, the role spans the automation of low-level business functional tests through to mid-level system integration tests. The successful candidate will have to co-ordinate with Operations Change Business Analysis team, Development teams, and Project managers, as well as testing teams. The successful candidate will have an excellent QA background with experience of a variety of automation test tools, technologies and have business domain expertise and experience of delivery in complex fast moving environments. Excellent communication skills will be vital in this role. The role will report to the Test Manager and work day to day with the Test Lead. Required Skills and Experience * Extensive automation testing experience in Investment Banking IT, preparing and executing automated tests on a Financial platforms.
LSEG (London Stock Exchange Group) is more than a diversified global financial markets infrastructure and data business. We are dedicated, open-access partners with a dedication to excellence in delivering the services our customers expect from us. With extensive experience, deep knowledge and worldwide presence across financial markets, we enable businesses and economies around the world to fund innovation, manage risk and create jobs. Its how weve contributed to supporting the financial stability and growth of communities and economies globally for more than 300 years. Through a comprehensive suite of trusted financial market infrastructure services and our open-access model we provide the flexibility, stability and trust that enable our customers to pursue their ambitions with confidence and clarity.
LSEG (London Stock Exchange Group) is more than a diversified global financial markets infrastructure and data business. We are dedicated, open-access partners with a dedication to excellence in delivering the services our customers expect from us. With extensive experience, deep knowledge and worldwide presence across financial markets, we enable businesses and economies around the world to fund innovation, manage risk and create jobs. Its how weve contributed to supporting the financial stability and growth of communities and economies globally for more than 300 years. Through a comprehensive suite of trusted financial market infrastructure services and our open-access model we provide the flexibility, stability and trust that enable our customers to pursue their ambitions with confidence and clarity.
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Define and govern API-led connectivity and enterprise integration patterns * Deep understanding of MuleSoft architecture, integration patterns, and API-led design
Define and govern API-led connectivity and enterprise integration patterns * Deep understanding of MuleSoft architecture, integration patterns, and API-led design
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Along with this you should also have hands on experience with API testing tools (e.g., Postman, REST Assured) and performance tools (e.g., JMeter, Gatling).
Along with this you should also have hands on experience with API testing tools (e.g., Postman, REST Assured) and performance tools (e.g., JMeter, Gatling).
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The successful applicant will have comprehensive expertise in Microsoft Azure services, Web API, Azure App Service, .NET Core, and Visual Studio. * Design and implement scalable cloud solutions utilizing Azure App Service, Web API, and .NET Core. * Define architecture patterns for microservices, API management, and integration with enterprise systems. * Utilize Azure Functions, Azure Logic Apps, Azure API Management, and Azure Storage to develop robust applications. * Expertise in Microsoft Azure services, including App Service, Functions, API Management, Storage, and Networking. * Strong knowledge of .NET Core, Web API, C#, and Visual Studio.
The successful applicant will have comprehensive expertise in Microsoft Azure services, Web API, Azure App Service, .NET Core, and Visual Studio. * Design and implement scalable cloud solutions utilizing Azure App Service, Web API, and .NET Core. * Define architecture patterns for microservices, API management, and integration with enterprise systems. * Utilize Azure Functions, Azure Logic Apps, Azure API Management, and Azure Storage to develop robust applications. * Expertise in Microsoft Azure services, including App Service, Functions, API Management, Storage, and Networking. * Strong knowledge of .NET Core, Web API, C#, and Visual Studio.
Skilled in API development and microservices architecture
Skilled in API development and microservices architecture
The core tech stack is: Java 8+, Spring MVC, SpringBoot, REST API's and using build tools such as Maven/Gradle.
The core tech stack is: Java 8+, Spring MVC, SpringBoot, REST API's and using build tools such as Maven/Gradle.
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Expertise in system and API design, scalability, and performance tuning
Expertise in system and API design, scalability, and performance tuning
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Senior Frontend Developer
Senior Frontend Developer
Pathfinder Business Solutions Ltd
Milton Keynes (MK9), MK9 3QA
From £50,000 to £60,000 per annum Full Benefits Pack
REST-based API development
REST-based API development
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Experience building maintainable and testable code bases, including API design and unit testing techniques
Experience building maintainable and testable code bases, including API design and unit testing techniques
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Build, fine-tune, and evaluate LLM-based Q&A models using frameworks like AWS Bedrock, Langchain, HuggingFace Transformers or OpenAI API.
Build, fine-tune, and evaluate LLM-based Q&A models using frameworks like AWS Bedrock, Langchain, HuggingFace Transformers or OpenAI API.
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Deep knowledge of REST API design, scalability, fault tolerance, and performance optimization.
Deep knowledge of REST API design, scalability, fault tolerance, and performance optimization.
Familiarity with REST API and Soap Services
Familiarity with REST API and Soap Services
Microservices architecture, API-first approach, containerisation (Docker/Kubernetes), CI/CD pipelines * Knowledge of integration patterns, API gateways, and cloud-native deployments
Microservices architecture, API-first approach, containerisation (Docker/Kubernetes), CI/CD pipelines * Knowledge of integration patterns, API gateways, and cloud-native deployments