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66 Permanent API jobs in West London + 20 miles
184 exact matches jobs are outside your preferred location
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A World-Changing Company - Palantir builds the worlds leading software for data-driven decisions and operations. By bringing the right data to the people who need it, our platforms empower our partners to develop lifesaving drugs, forecast supply chain disruptions, locate missing children, and more. The Role - Backend Software Engineers at Palantir build software at scale to transform how organizations use data. Our Software Engineers are involved throughout the product lifecycle, from idea generation, design, prototyping, and production delivery. You will collaborate closely with technical and non-technical teammates to understand our customers' problems and build products that solve them. We encourage movement across teams to share context, skills, and experience, so you'll learn about many different technologies and aspects of each product.
A World-Changing Company - Palantir builds the worlds leading software for data-driven decisions and operations. By bringing the right data to the people who need it, our platforms empower our partners to develop lifesaving drugs, forecast supply chain disruptions, locate missing children, and more. The Role - Backend Software Engineers at Palantir build software at scale to transform how organizations use data. Our Software Engineers are involved throughout the product lifecycle, from idea generation, design, prototyping, and production delivery. You will collaborate closely with technical and non-technical teammates to understand our customers' problems and build products that solve them. We encourage movement across teams to share context, skills, and experience, so you'll learn about many different technologies and aspects of each product.
A World-Changing Company - Palantir builds the worlds leading software for data-driven decisions and operations. By bringing the right data to the people who need it, our platforms empower our partners to develop lifesaving drugs, forecast supply chain disruptions, locate missing children, and more. The Role - Palantir Foundry is an end-to-end platform for data-driven decision-making. We're transforming the way organisations securely integrate their data, so they can then build reliable, critical applications atop that unified foundation. Our customers use Foundry to perform rich analyses that drive core operations within their organisations. They can also build sophisticated, full-fledged programs, such as common operating pictures, alert-triaging inboxes, and resource allocation planning tools driven by rich-ML models.
A World-Changing Company - Palantir builds the worlds leading software for data-driven decisions and operations. By bringing the right data to the people who need it, our platforms empower our partners to develop lifesaving drugs, forecast supply chain disruptions, locate missing children, and more. The Role - Palantir Foundry is an end-to-end platform for data-driven decision-making. We're transforming the way organisations securely integrate their data, so they can then build reliable, critical applications atop that unified foundation. Our customers use Foundry to perform rich analyses that drive core operations within their organisations. They can also build sophisticated, full-fledged programs, such as common operating pictures, alert-triaging inboxes, and resource allocation planning tools driven by rich-ML models.
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Location: London - 1x a month - Salary: Up to £120,000 (D.O.E) + benefits - Fruition Group are partnering with a high-growth Insurtech unicorn that's scaling its engineering function. This is a unique chance to work across both proven, revenue-generating products and greenfield initiatives that are reshaping the future of insurance. It's an ideal role for a driven Lead Engineer who thrives in ambitious environments and wants to make a tangible impact. As a Lead Backend Engineer, you'll take ownership of designing and scaling cloud-native backend systems. You'll work primarily with Python (FastAPI) and play a key role in shaping the architecture of microservices that support millions of users. Beyond hands-on development, you'll provide technical leadership, mentor team members, and influence strategic engineering decisions.
Location: London - 1x a month - Salary: Up to £120,000 (D.O.E) + benefits - Fruition Group are partnering with a high-growth Insurtech unicorn that's scaling its engineering function. This is a unique chance to work across both proven, revenue-generating products and greenfield initiatives that are reshaping the future of insurance. It's an ideal role for a driven Lead Engineer who thrives in ambitious environments and wants to make a tangible impact. As a Lead Backend Engineer, you'll take ownership of designing and scaling cloud-native backend systems. You'll work primarily with Python (FastAPI) and play a key role in shaping the architecture of microservices that support millions of users. Beyond hands-on development, you'll provide technical leadership, mentor team members, and influence strategic engineering decisions.
Location: London - 1x a month - Salary: Up to £95,000 (D.O.E) + benefits - Fruition Group working with a leading Insurtech unicorn on a mission to transform the insurance industry. Their products have already generated millions in revenue, and now they're investing heavily in new innovations that will shape the sector for years to come. This is an exciting opportunity for a motivated Senior Engineer who wants to grow in a high-performing, forward-thinking business. As a Senior Backend Engineer, you'll play a central role in building and scaling the systems that power their insurance platform. You'll focus on developing Python-based cloud microservices (FastAPI preferred), contributing to the architecture of resilient, high-performance systems, and collaborating with a cross-functional team to deliver features at pace.
Location: London - 1x a month - Salary: Up to £95,000 (D.O.E) + benefits - Fruition Group working with a leading Insurtech unicorn on a mission to transform the insurance industry. Their products have already generated millions in revenue, and now they're investing heavily in new innovations that will shape the sector for years to come. This is an exciting opportunity for a motivated Senior Engineer who wants to grow in a high-performing, forward-thinking business. As a Senior Backend Engineer, you'll play a central role in building and scaling the systems that power their insurance platform. You'll focus on developing Python-based cloud microservices (FastAPI preferred), contributing to the architecture of resilient, high-performance systems, and collaborating with a cross-functional team to deliver features at pace.
We are seeking an experienced Front-end Engineer to help build and evolve a web-based platform for reinforcement learning (RL) training and RLOps. You will design, implement, and optimise user-facing interfaces and front-end systems that support large-scale RL model development and deployment. Responsibilities * Develop scalable, reliable front-end architecture for an RL training and management platform * Translate requirements into high-quality user interfaces and workflows * Collaborate with designers and engineers to implement visual design within brand guidelines * Ensure cross-browser and cross-device compatibility, resolving UI/UX issues * Optimise performance, including load times and runtime efficiency * Ensure accessibility compliance (e.g., WCAG) * Identify and resolve user-facing bugs and usability issues
We are seeking an experienced Front-end Engineer to help build and evolve a web-based platform for reinforcement learning (RL) training and RLOps. You will design, implement, and optimise user-facing interfaces and front-end systems that support large-scale RL model development and deployment. Responsibilities * Develop scalable, reliable front-end architecture for an RL training and management platform * Translate requirements into high-quality user interfaces and workflows * Collaborate with designers and engineers to implement visual design within brand guidelines * Ensure cross-browser and cross-device compatibility, resolving UI/UX issues * Optimise performance, including load times and runtime efficiency * Ensure accessibility compliance (e.g., WCAG) * Identify and resolve user-facing bugs and usability issues
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We're seeking an experienced Senior Full Stack Developer to join our clients expanding technology team. In this role, you'll be instrumental in designing, developing, and maintaining high-quality, scalable web applications. You'll work across the full stack, collaborating closely with colleagues to deliver impactful, user-focused solutions. Key Responsibilities * Develop and maintain modern web applications using C# .NET (Core/Framework) and React. * Work with cross-functional teams to define requirements and deliver new features. * Write clean, scalable, and well-tested code. * Diagnose and resolve application issues to ensure optimal performance. You will have - * 3+ years' experience as a Full Stack Developer. * Strong hands-on expertise with C# .NET (Core) and React. * Good understanding of REST APIs, SQL/NoSQL databases, and Git version control.
We're seeking an experienced Senior Full Stack Developer to join our clients expanding technology team. In this role, you'll be instrumental in designing, developing, and maintaining high-quality, scalable web applications. You'll work across the full stack, collaborating closely with colleagues to deliver impactful, user-focused solutions. Key Responsibilities * Develop and maintain modern web applications using C# .NET (Core/Framework) and React. * Work with cross-functional teams to define requirements and deliver new features. * Write clean, scalable, and well-tested code. * Diagnose and resolve application issues to ensure optimal performance. You will have - * 3+ years' experience as a Full Stack Developer. * Strong hands-on expertise with C# .NET (Core) and React. * Good understanding of REST APIs, SQL/NoSQL databases, and Git version control.
We're seeking an experienced Senior Full Stack Developer to join our clients expanding technology team. In this role, you'll be instrumental in designing, developing, and maintaining high-quality, scalable web applications. You'll work across the full stack, collaborating closely with colleagues to deliver impactful, user-focused solutions. Key Responsibilities * Develop and maintain modern web applications using C# .NET (Core/Framework) and React. * Work with cross-functional teams to define requirements and deliver new features. * Write clean, scalable, and well-tested code. * Diagnose and resolve application issues to ensure optimal performance. You will have - * 3+ years' experience as a Full Stack Developer. * Strong hands-on expertise with C# .NET (Core) and React. * Good understanding of REST APIs, SQL/NoSQL databases, and Git version control.
We're seeking an experienced Senior Full Stack Developer to join our clients expanding technology team. In this role, you'll be instrumental in designing, developing, and maintaining high-quality, scalable web applications. You'll work across the full stack, collaborating closely with colleagues to deliver impactful, user-focused solutions. Key Responsibilities * Develop and maintain modern web applications using C# .NET (Core/Framework) and React. * Work with cross-functional teams to define requirements and deliver new features. * Write clean, scalable, and well-tested code. * Diagnose and resolve application issues to ensure optimal performance. You will have - * 3+ years' experience as a Full Stack Developer. * Strong hands-on expertise with C# .NET (Core) and React. * Good understanding of REST APIs, SQL/NoSQL databases, and Git version control.
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Job Title: Observability Developer / Engineer - Location: Hybrid (UK, with travel as required) Employment Type: Full-time - This role is with Morela please respond to for further informaiton - Do you want to be part of something special? Morela is proud to represent our exclusive client, a fast-growing start-up transforming Service Operations. Led by industry leaders with a proven track record of building and scaling successful businesses, this company is redefining how enterprises monitor, manage, and optimise IT operations. This is your chance to join a team shaping the future of observability and operational intelligence from the ground up. We are seeking a skilled Observability Developer to design, build, and optimise observability solutions that help enterprise clients gain actionable insights from their logs, metrics, traces, and events.
Job Title: Observability Developer / Engineer - Location: Hybrid (UK, with travel as required) Employment Type: Full-time - This role is with Morela please respond to for further informaiton - Do you want to be part of something special? Morela is proud to represent our exclusive client, a fast-growing start-up transforming Service Operations. Led by industry leaders with a proven track record of building and scaling successful businesses, this company is redefining how enterprises monitor, manage, and optimise IT operations. This is your chance to join a team shaping the future of observability and operational intelligence from the ground up. We are seeking a skilled Observability Developer to design, build, and optimise observability solutions that help enterprise clients gain actionable insights from their logs, metrics, traces, and events.
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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Were looking for an enthusiastic Senior/Staff Software Engineer who knows about graphics and GPU drivers, has a curious mind, and a passion for making high-impact products to join the Customer Engineering Team at ARMs GPU Group! In this role you will work on flagship devices with the world's most successful mobile companies. Take the skills you have developed in early engineering career and see them used in a wider business context. Be part of and be well supported by a team of experts! * Developing the high-level graphics APIs of our Mali driver: Vulkan, OpenCL, OpenGL ES, EGL. * Working with some of the biggest names in the consumer electronics space on their latest and greatest platforms. * Integrate and optimise our software into their flagship devices to show the world what Mali can do. * Experienced with graphics APIs such as Vulkan, OpenGL ES, and EGL (Khronos)
Were looking for an enthusiastic Senior/Staff Software Engineer who knows about graphics and GPU drivers, has a curious mind, and a passion for making high-impact products to join the Customer Engineering Team at ARMs GPU Group! In this role you will work on flagship devices with the world's most successful mobile companies. Take the skills you have developed in early engineering career and see them used in a wider business context. Be part of and be well supported by a team of experts! * Developing the high-level graphics APIs of our Mali driver: Vulkan, OpenCL, OpenGL ES, EGL. * Working with some of the biggest names in the consumer electronics space on their latest and greatest platforms. * Integrate and optimise our software into their flagship devices to show the world what Mali can do. * Experienced with graphics APIs such as Vulkan, OpenGL ES, and EGL (Khronos)
FTSE Russell | LSEG Technology - FTSE Russell is a leading global provider of financial services, specializing in the creation and management of indexes, data, and analytic solutions. A subsidiary of the London Stock Exchange Group (LSEG), FTSE Russell supports investors worldwide in making informed decisions across asset classes, investment strategies, and market segments. Its products are trusted by institutional and retail investors, asset managers, and pension funds to benchmark performance, build investment portfolios, and manage risk. With a reputation for innovation, transparency, and robust governance, FTSE Russell plays a critical role in shaping global financial markets. FTSE Russell is seeking a junior software engineer to be part a dynamic team building the distribution capabilities of our index products to the financial community worldwide.
FTSE Russell | LSEG Technology - FTSE Russell is a leading global provider of financial services, specializing in the creation and management of indexes, data, and analytic solutions. A subsidiary of the London Stock Exchange Group (LSEG), FTSE Russell supports investors worldwide in making informed decisions across asset classes, investment strategies, and market segments. Its products are trusted by institutional and retail investors, asset managers, and pension funds to benchmark performance, build investment portfolios, and manage risk. With a reputation for innovation, transparency, and robust governance, FTSE Russell plays a critical role in shaping global financial markets. FTSE Russell is seeking a junior software engineer to be part a dynamic team building the distribution capabilities of our index products to the financial community worldwide.
FTSE Russell | LSEG Technology - FTSE Russell is a leading global provider of financial services, specializing in the creation and management of indexes, data, and analytic solutions. A subsidiary of the London Stock Exchange Group (LSEG), FTSE Russell supports investors worldwide in making informed decisions across asset classes, investment strategies, and market segments. Its products are trusted by institutional and retail investors, asset managers, and pension funds to benchmark performance, build investment portfolios, and manage risk. With a reputation for innovation, transparency, and robust governance, FTSE Russell plays a critical role in shaping global financial markets. FTSE Russell is seeking a senior software engineer to be part a dynamic team of software engineers building all distribution capabilities of our index products to the financial community wor
FTSE Russell | LSEG Technology - FTSE Russell is a leading global provider of financial services, specializing in the creation and management of indexes, data, and analytic solutions. A subsidiary of the London Stock Exchange Group (LSEG), FTSE Russell supports investors worldwide in making informed decisions across asset classes, investment strategies, and market segments. Its products are trusted by institutional and retail investors, asset managers, and pension funds to benchmark performance, build investment portfolios, and manage risk. With a reputation for innovation, transparency, and robust governance, FTSE Russell plays a critical role in shaping global financial markets. FTSE Russell is seeking a senior software engineer to be part a dynamic team of software engineers building all distribution capabilities of our index products to the financial community wor
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Senior Machine Learning Engineer - Salary: £70,000-£90,000 - Location: London (Hybrid) The Opportunity - We're looking for a Senior Machine Learning Engineer to help design, build, and deliver next-generation AI systems. You will work across LLMs, retrieval-augmented generation (RAG), and modern agent frameworks to transform large, unstructured data into meaningful insights and production-ready capabilities. This is a hands-on role within a growing AI team, offering the chance to shape architecture, build scalable pipelines, and ship features that directly impact users. Responsibilities * Develop, integrate, and fine-tune LLMs for natural-language understanding, reasoning, and workflow automation. * Build agentic/LLM-driven workflows for multi-step decision making across diverse data sources. * Architect and deliver ML features such as pattern recognition, entity extr
Senior Machine Learning Engineer - Salary: £70,000-£90,000 - Location: London (Hybrid) The Opportunity - We're looking for a Senior Machine Learning Engineer to help design, build, and deliver next-generation AI systems. You will work across LLMs, retrieval-augmented generation (RAG), and modern agent frameworks to transform large, unstructured data into meaningful insights and production-ready capabilities. This is a hands-on role within a growing AI team, offering the chance to shape architecture, build scalable pipelines, and ship features that directly impact users. Responsibilities * Develop, integrate, and fine-tune LLMs for natural-language understanding, reasoning, and workflow automation. * Build agentic/LLM-driven workflows for multi-step decision making across diverse data sources. * Architect and deliver ML features such as pattern recognition, entity extr
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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.
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Software Developer (.Net)
Software Developer (.Net)
Spectrum It Recruitment Limited
Reading (RG1)
£50000 - £60000 per annum + Benefits & Progression
API Development
API Development
The Service is one of the fastest growing streams in the LCH business lines and is looking to build on recent successes and further increase market share through modernising and enhancing our external facing application and API by delivering powerful and scalable functionality to meet evolving market demands.
The Service is one of the fastest growing streams in the LCH business lines and is looking to build on recent successes and further increase market share through modernising and enhancing our external facing application and API by delivering powerful and scalable functionality to meet evolving market demands.
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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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Integration & API Testing - proficiency with REST/OData service testing using tools like Postman or SoapUI
Integration & API Testing - proficiency with REST/OData service testing using tools like Postman or SoapUI
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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Understanding of cloud architectures, API-driven platforms, and financial data security standards.
Understanding of cloud architectures, API-driven platforms, and financial data security standards.
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
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Data exchange and processing skills (e.g. ETL, ESB, API...)
Data exchange and processing skills (e.g. ETL, ESB, API...)
FEATURED
Design, develop, and deliver custom solutions within Planon's API framework.
Design, develop, and deliver custom solutions within Planon's API framework.
FEATURED