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25 Permanent API jobs in Welwyn Garden City + 20 miles
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In this critical role, youll develop and maintain REST API over serverless functions using TypeScript; youll also design and implement scalable PostgreSQL schemas and data models. Other organisations may call this role Software Engineer, Software Developer, Back End Software Engineer, Server-Side Developer, Full Stack Developer, or API Developer.
In this critical role, youll develop and maintain REST API over serverless functions using TypeScript; youll also design and implement scalable PostgreSQL schemas and data models. Other organisations may call this role Software Engineer, Software Developer, Back End Software Engineer, Server-Side Developer, Full Stack Developer, or API Developer.
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Familiarity with REST API.
Familiarity with REST API.
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Design and communicate system architecture diagrams, data flows, and API integrations * Hands-on experience in solution architecture and API design
Design and communicate system architecture diagrams, data flows, and API integrations * Hands-on experience in solution architecture and API design
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QA Specialist - Hybrid Remote
QA Specialist - Hybrid Remote
VERTECH GROUP (UK) LTD
NW3, North West London
From £50,000 to £55,000 per annum + Benefits
Experience with API testing and familiarity with tools like Postman, SoapUI, or similar
Experience with API testing and familiarity with tools like Postman, SoapUI, or similar
Strong background in software architecture, microservices, and API design.
Strong background in software architecture, microservices, and API design.
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Systems Engineer - Enterprise Technology
Systems Engineer - Enterprise Technology
Randstad Digital
EC1, City of London
£250000 - £350000 per annum
Proficiency with the administration, integration, and API capabilities of SaaS platforms such as Okta, Google Workspace, Atlassian products, and Slack. * Familiarity with authentication and provisioning methods like SAML, OIDC, SCIM, and non-standard API-based workflows.
Proficiency with the administration, integration, and API capabilities of SaaS platforms such as Okta, Google Workspace, Atlassian products, and Slack. * Familiarity with authentication and provisioning methods like SAML, OIDC, SCIM, and non-standard API-based workflows.
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Backend Engineer - Scale Systems with Real Impact ?? Tired of tinkering at the edges? Want to actually shape the backbone of a platform that's transforming how the world's biggest enterprises run their tech? This is one of those rare roles where you get in early, build the foundations, and watch your work scale across global businesses. We're working with a high-growth London startup on a mission to reinvent enterprise software. Their AI-driven platform is already saving household-name customers millions in IT costs, shaving months off ERP project timelines, and making sense of the mess that legacy systems leave behind. SAP is just the beginning - they're building a whole new category of Enterprise System Intelligence. The Role * Build core systems capable of handling tens of millions of lines of code and large-scale LLM workloads.
Backend Engineer - Scale Systems with Real Impact ?? Tired of tinkering at the edges? Want to actually shape the backbone of a platform that's transforming how the world's biggest enterprises run their tech? This is one of those rare roles where you get in early, build the foundations, and watch your work scale across global businesses. We're working with a high-growth London startup on a mission to reinvent enterprise software. Their AI-driven platform is already saving household-name customers millions in IT costs, shaving months off ERP project timelines, and making sense of the mess that legacy systems leave behind. SAP is just the beginning - they're building a whole new category of Enterprise System Intelligence. The Role * Build core systems capable of handling tens of millions of lines of code and large-scale LLM workloads.
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£50,000 - £75,000 DOE | Full-time, on-site | Start: ASAP - Join a global logistics company that's embracing the power of AI to transform the way it operates. This is an opportunity to be part of a forward-thinking team that's leveraging the latest in Large Language Models (LLMs) and automation to drive real business value. As an AI Solutions Engineer, you'll design, build, and implement intelligent automation solutions using cutting-edge AI technologies. Working closely with business stakeholders, you'll identify opportunities for innovation, prototype new ideas, and deliver scalable AI-driven systems that make a measurable impact. * Collaborating with business teams to uncover and define AI/automation opportunities. * Engineering and optimising prompts to ensure consistent, high-quality LLM outputs.
£50,000 - £75,000 DOE | Full-time, on-site | Start: ASAP - Join a global logistics company that's embracing the power of AI to transform the way it operates. This is an opportunity to be part of a forward-thinking team that's leveraging the latest in Large Language Models (LLMs) and automation to drive real business value. As an AI Solutions Engineer, you'll design, build, and implement intelligent automation solutions using cutting-edge AI technologies. Working closely with business stakeholders, you'll identify opportunities for innovation, prototype new ideas, and deliver scalable AI-driven systems that make a measurable impact. * Collaborating with business teams to uncover and define AI/automation opportunities. * Engineering and optimising prompts to ensure consistent, high-quality LLM outputs.
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Senior Data Engineer SQL BigQuery GCP
Senior Data Engineer SQL BigQuery GCP
Client Server
EC2A, City of London
£90000 - £110000 per annum + benefits
Are you a data technologist with Media Streaming experience? You could be progressing your career in a senor, hands-on role at one of Europe's most successful streaming and social media platforms. * Salary to £110k * Employee stock options plan * Flexible vacation and public holidays allowing you 35 days of annual leave * Creativity and Wellness package covering everything from gym memberships, photography, language courses, books * Professional development allowance covering things like books, conferences and training * Remote working most of the time if desired (x1 month in London) * A sociable office environment with free snacks, drinks and lunch if you are in the office - As a Senior Data Engineer you'll design, build and maintain high-performance services for content modelling, serving and integration, develop data pipelines (both batch and streaming) using cloud
Are you a data technologist with Media Streaming experience? You could be progressing your career in a senor, hands-on role at one of Europe's most successful streaming and social media platforms. * Salary to £110k * Employee stock options plan * Flexible vacation and public holidays allowing you 35 days of annual leave * Creativity and Wellness package covering everything from gym memberships, photography, language courses, books * Professional development allowance covering things like books, conferences and training * Remote working most of the time if desired (x1 month in London) * A sociable office environment with free snacks, drinks and lunch if you are in the office - As a Senior Data Engineer you'll design, build and maintain high-performance services for content modelling, serving and integration, develop data pipelines (both batch and streaming) using cloud
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Senior Backend Engineer TypeScript Node.js
Senior Backend Engineer TypeScript Node.js
Client Server
EC2A, City of London
£65000 - £80000 per annum + benefits
Senior Backend Engineer / Developer (TypeScript Node.js) Remote UK to £80k - Are you a senior, hands-on Backend Engineer looking for an opportunity to take ownership and progress your career at a scaling tech company? You could be joining a growing games company that combines state of the art technology, gaming and luxury fashion. As a Senior Backend Engineer you'll join the team as they scale the product to support millions of users. You'll design and deliver high-quality, maintainable backend code and features using TypeScript and Node.js that is aligned with established codebase architectural standards and covered by tests as well as supporting backend system performance and reliability, helping to maintain 99% uptime SLA. You'll design, implement and extend robust APIs and microservices supporting gameplay, user management, platform and content management systems,
Senior Backend Engineer / Developer (TypeScript Node.js) Remote UK to £80k - Are you a senior, hands-on Backend Engineer looking for an opportunity to take ownership and progress your career at a scaling tech company? You could be joining a growing games company that combines state of the art technology, gaming and luxury fashion. As a Senior Backend Engineer you'll join the team as they scale the product to support millions of users. You'll design and deliver high-quality, maintainable backend code and features using TypeScript and Node.js that is aligned with established codebase architectural standards and covered by tests as well as supporting backend system performance and reliability, helping to maintain 99% uptime SLA. You'll design, implement and extend robust APIs and microservices supporting gameplay, user management, platform and content management systems,
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CRM Configuration Specialist - Remote UK - Curo, Xplan, Intelligent Office
CRM Configuration Specialist - Remote UK - Curo, Xplan, Intelligent Office
Hireful
Euston, NW1
50 - 60K + Bonus + Equity + 25 Days + 5% Pension + Health
Want to become a go-to CRM configuration specialist, while working remotely with equity upside? Great opportunity to join rapidly growing consultancy delivering to the Wealth Management / IFA space. A company that believes in developing its people and focuses on delivery rather than presenteeism. Role CRM Configuration Specialist aka CRM Consultant, CRM Analyst, Implementation Consultant - Location Remote UK, Flex Start / Finish times - Salary 50 - 60K, Bonus, Equity, 5% Pension, 25 Days, Health plan - We’re seeking a Configuration Specialist to configure and optimise platforms such as Curo Xplan, Intelligent Office or Plannr helping financial services firms streamline operations and deliver impact. * Hands-on experience configuring CRM systems - Ideally in Wealth Management * Strong analytical skills to translate business needs into solutions
Want to become a go-to CRM configuration specialist, while working remotely with equity upside? Great opportunity to join rapidly growing consultancy delivering to the Wealth Management / IFA space. A company that believes in developing its people and focuses on delivery rather than presenteeism. Role CRM Configuration Specialist aka CRM Consultant, CRM Analyst, Implementation Consultant - Location Remote UK, Flex Start / Finish times - Salary 50 - 60K, Bonus, Equity, 5% Pension, 25 Days, Health plan - We’re seeking a Configuration Specialist to configure and optimise platforms such as Curo Xplan, Intelligent Office or Plannr helping financial services firms streamline operations and deliver impact. * Hands-on experience configuring CRM systems - Ideally in Wealth Management * Strong analytical skills to translate business needs into solutions
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Backend Engineer Python
Backend Engineer Python
Plexus Resource Solutions Ltd
EC1, City of London
From £90,000 to £120,000 per annum
Backend Engineer - On-Chain Social Network - Remote £90k £120k - Plexus are working with an on-chain social network that empowers people to express themselves, connect with others, and explore the value of imagination. To support our growth and deliver a world-class experience, were looking for a Backend Engineer to join our core product team. Responsibilities * Work closely with the team to design, build, and deliver new product features * Develop and maintain the APIs that power our platform * Contribute to system reliability by taking part in our on-call rotation - Requirements * Solid experience with Python, GraphQL, and MongoDB * Flexibility to move across the stack when needed * Hands-on experience in blockchain development * Strong product intuition with a focus on user experience - Benefits * Competitive salary * Top-quality medical, dental & vision insurance
Backend Engineer - On-Chain Social Network - Remote £90k £120k - Plexus are working with an on-chain social network that empowers people to express themselves, connect with others, and explore the value of imagination. To support our growth and deliver a world-class experience, were looking for a Backend Engineer to join our core product team. Responsibilities * Work closely with the team to design, build, and deliver new product features * Develop and maintain the APIs that power our platform * Contribute to system reliability by taking part in our on-call rotation - Requirements * Solid experience with Python, GraphQL, and MongoDB * Flexibility to move across the stack when needed * Hands-on experience in blockchain development * Strong product intuition with a focus on user experience - Benefits * Competitive salary * Top-quality medical, dental & vision insurance
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ABAP Developer - Break out of the SAP Box
ABAP Developer - Break out of the SAP Box
LJ Recruitment Limited
EC1, City of London
£50000 - £75000 per annum
ABAP Developer ? AI / Startup Role?? Most ABAP roles keep you maintaining the same old codebase. This one lets you take your SAP expertise and plug it straight into a modern AI platform that's transforming how global enterprises run their tech. This London startup is tackling a multi-billion-dollar problem: helping the world's biggest companies turn ERP chaos into clarity. Their AI engine saves millions in IT costs, accelerates project timelines by months, and modernises decades-old systems in ways that have never been done before. This is a role for those who live and breathe tech. Hours run 9am-7pm, and the expectation is clear: hard work and full commitment are what make the difference here. What you'll do * Write and optimise ABAP while shaping how AI agents interpret SAP. * Go beyond SAP, contribute to backend services, APIs, and infrastructure.
ABAP Developer ? AI / Startup Role?? Most ABAP roles keep you maintaining the same old codebase. This one lets you take your SAP expertise and plug it straight into a modern AI platform that's transforming how global enterprises run their tech. This London startup is tackling a multi-billion-dollar problem: helping the world's biggest companies turn ERP chaos into clarity. Their AI engine saves millions in IT costs, accelerates project timelines by months, and modernises decades-old systems in ways that have never been done before. This is a role for those who live and breathe tech. Hours run 9am-7pm, and the expectation is clear: hard work and full commitment are what make the difference here. What you'll do * Write and optimise ABAP while shaping how AI agents interpret SAP. * Go beyond SAP, contribute to backend services, APIs, and infrastructure.
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About This Opportunity - We are supporting Welldone Consulting in their search for a founding Head of Delivery. This is a unique opportunity to establish, shape, and grow a business at the forefront of accessible mobile app consulting in the UK. About Welldone Consulting - Welldone Consulting focuses on building future-ready, inclusive, and commercially strategic mobile apps. Their mission is to help organisations not just comply with the European Accessibility Act but also to drive greater loyalty, adoption, and revenue by improving mobile user experiences for everyone. Role Purpose * Lead client engagements from initial contact to completion. * Develop frameworks for delivery and build an associate consultant model. * Serve as the public face and thought leader for the consultancy. Key Responsibilities - Client Engagement * Act as the main point of contact through p
About This Opportunity - We are supporting Welldone Consulting in their search for a founding Head of Delivery. This is a unique opportunity to establish, shape, and grow a business at the forefront of accessible mobile app consulting in the UK. About Welldone Consulting - Welldone Consulting focuses on building future-ready, inclusive, and commercially strategic mobile apps. Their mission is to help organisations not just comply with the European Accessibility Act but also to drive greater loyalty, adoption, and revenue by improving mobile user experiences for everyone. Role Purpose * Lead client engagements from initial contact to completion. * Develop frameworks for delivery and build an associate consultant model. * Serve as the public face and thought leader for the consultancy. Key Responsibilities - Client Engagement * Act as the main point of contact through p
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£80,000 - £85,000 - Well-established and highly profitable construction engineering business is seeking an experienced IT Applications Manager to join them on a permanent basis. This is a critical leadership role within an organisation undergoing significant digital transformation, with ambitious growth and acquisition plans driving demand for scalable, standardised and efficient business applications. Reporting into the Head of IT, you will lead the delivery, governance and optimisation of business applications across the enterprise. This role blends strategic oversight, hands-on expertise with modern low-code/no-code platforms and direct leadership of a multidisciplinary applications team. The IT Applications Manager will oversee a suite of core enterprise systems, including but not limited to: Workday, UKG (Kronos), COINS, SharePoint, Snowflake, Autodesk Constructi
£80,000 - £85,000 - Well-established and highly profitable construction engineering business is seeking an experienced IT Applications Manager to join them on a permanent basis. This is a critical leadership role within an organisation undergoing significant digital transformation, with ambitious growth and acquisition plans driving demand for scalable, standardised and efficient business applications. Reporting into the Head of IT, you will lead the delivery, governance and optimisation of business applications across the enterprise. This role blends strategic oversight, hands-on expertise with modern low-code/no-code platforms and direct leadership of a multidisciplinary applications team. The IT Applications Manager will oversee a suite of core enterprise systems, including but not limited to: Workday, UKG (Kronos), COINS, SharePoint, Snowflake, Autodesk Constructi
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Location: London - 1x a month - Salary: £95,000 - £120,000 + equity + benefits - An established, global technology business within the hospitality-tech industry is seeking an accomplished Principal Software Engineer to lead the design and delivery of next-generation digital solutions. This is an opportunity to shape greenfield projects from the ground up - architecting scalable, data-driven systems that empower venues to deliver seamless guest experiences and drive long-term innovation. What will I be doing? * Lead the technical vision and architectural direction across complex backend systems, ensuring scalability, reliability, and performance. * Partner closely with engineering leadership to define best practices, coding standards, and long-term technical strategy. * Design, develop, and oversee the delivery of robust, production-grade software built using Python, D
Location: London - 1x a month - Salary: £95,000 - £120,000 + equity + benefits - An established, global technology business within the hospitality-tech industry is seeking an accomplished Principal Software Engineer to lead the design and delivery of next-generation digital solutions. This is an opportunity to shape greenfield projects from the ground up - architecting scalable, data-driven systems that empower venues to deliver seamless guest experiences and drive long-term innovation. What will I be doing? * Lead the technical vision and architectural direction across complex backend systems, ensuring scalability, reliability, and performance. * Partner closely with engineering leadership to define best practices, coding standards, and long-term technical strategy. * Design, develop, and oversee the delivery of robust, production-grade software built using Python, D
Location: London 1x a month - Salary: £75,000 - £95,000 + equity + benefits - An established, global technology business within the hospitality-tech industry is seeking a talented Backend Software Engineer to help build and scale cutting-edge digital solutions. This is a chance to work on greenfield projects - building new, scalable products that help venues create seamless, data-driven guest experiences from the ground up. What will I be doing? * Design, develop, test, and maintain high-performance backend systems supporting real-time hospitality operations. * Take ownership of key features throughout the software development lifecycle - from technical design through to deployment and ongoing optimisation. * Collaborate with cross-functional teams including product, design, and data science to deliver innovative, customer-focused solutions.
Location: London 1x a month - Salary: £75,000 - £95,000 + equity + benefits - An established, global technology business within the hospitality-tech industry is seeking a talented Backend Software Engineer to help build and scale cutting-edge digital solutions. This is a chance to work on greenfield projects - building new, scalable products that help venues create seamless, data-driven guest experiences from the ground up. What will I be doing? * Design, develop, test, and maintain high-performance backend systems supporting real-time hospitality operations. * Take ownership of key features throughout the software development lifecycle - from technical design through to deployment and ongoing optimisation. * Collaborate with cross-functional teams including product, design, and data science to deliver innovative, customer-focused solutions.
Proficiency in cloud platforms, API development, message buses, DevOps practices, and languages such as C#, Python, or PHP
Proficiency in cloud platforms, API development, message buses, DevOps practices, and languages such as C#, Python, or PHP
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AI (artificial intelligence) DevOps Engineer
AI (artificial intelligence) DevOps Engineer
Huxley Associates
EC1, City of London
£60000 - £90000 per annum
You'll also ensure alignment with enterprise-grade security practices, including zero trust principles, identity-aware routing, and integration with Azure API Management and Application Gateway. * API Gateway, Azure API Management (APIM), Azure Application Gateway
You'll also ensure alignment with enterprise-grade security practices, including zero trust principles, identity-aware routing, and integration with Azure API Management and Application Gateway. * API Gateway, Azure API Management (APIM), Azure Application Gateway
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Data exchange and processing skills (e.g. ETL, ESB, API...)
Data exchange and processing skills (e.g. ETL, ESB, API...)
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Experience with API testing tools such as Postman.
Experience with API testing tools such as Postman.
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Principal Software Engineer - Unified Client Experience (UCX)
Principal Software Engineer - Unified Client Experience (UCX)
Hargreaves Lansdown
EC1, City of London
Up to £11500 per annum + Generous bonus, pension, PMI & more
Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services.
Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services.
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Senior Software Engineer - Unified Client Experience (UCX)
Senior Software Engineer - Unified Client Experience (UCX)
Hargreaves Lansdown
EC1, City of London
£75000 - £95000 per annum + Generous bonus, pension, PMI & more
Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services.
Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services.
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Software Engineering Manager - Unified Client Experience (UCX)
Software Engineering Manager - Unified Client Experience (UCX)
Hargreaves Lansdown
EC1, City of London
£90000 - £115000 per annum + Generous bonus, pension, PMI and more
Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services.
Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services.
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C# .NET Software Developer (Full time or Part time)
C# .NET Software Developer (Full time or Part time)
Gas Management Services Limited
Epping, Essex
Competitive
We have a great opportunity for a C# .NET Software Developer (Full time or Part time) to join our team in Cambridge. Apply with your CV and covering letter - Opportunity - We have a great opportunity for a C# .NET Software Developer to join our fantastic software development team based in Cambridge. This is an ideal role for someone who wants to join a friendly, small and highly technical team where you can have a real impact. The role - You will be embedded as a full-stack developer in one of our small agile development teams. You will collaborate alongside product owners, testers and other developers to develop features for our power-scheduling software product. Our view of agile software development is inspired by eXtreme Programming rather than Scrum. We focus more on the technical practices that enable agility, such as TDD, Pair Programming, SOLID, Simple Design
We have a great opportunity for a C# .NET Software Developer (Full time or Part time) to join our team in Cambridge. Apply with your CV and covering letter - Opportunity - We have a great opportunity for a C# .NET Software Developer to join our fantastic software development team based in Cambridge. This is an ideal role for someone who wants to join a friendly, small and highly technical team where you can have a real impact. The role - You will be embedded as a full-stack developer in one of our small agile development teams. You will collaborate alongside product owners, testers and other developers to develop features for our power-scheduling software product. Our view of agile software development is inspired by eXtreme Programming rather than Scrum. We focus more on the technical practices that enable agility, such as TDD, Pair Programming, SOLID, Simple Design