26 to 50 of 89 API Design Jobs in London

Lead Software Engineer - SDET

Hiring Organisation
17918
Location
Charing Cross, South West London, United Kingdom
advance your career while helping us deliver exceptional solutions. As a Lead Software Development Engineer in Test (SDET) in our technology team, you will design, build, and support automated testing frameworks for backend applications. You will collaborate closely with developers and engineers to ensure robust, scalable, and reliable systems. … role in driving innovation and efficiency within our testing processes. Together, we foster a culture of learning, teamwork, and excellence. Job Responsibilities: Design and support automated testing frameworks for backend applications Develop and maintain test scripts using Python3 and pytest Implement and validate REST API functionality and principles ...

Lead Software Engineer - SDET

Hiring Organisation
J.P. Morgan
Location
London, UK
Employment Type
Full-time
your career while helping us deliver exceptional solutions. \n As a Lead Software Development Engineer in Test (SDET) in our technology team, you will design, build, and support automated testing frameworks for backend applications. You will collaborate closely with developers and engineers to ensure robust, scalable, and reliable systems. … driving innovation and efficiency within our testing processes. Together, we foster a culture of learning, teamwork, and excellence. \n Job Responsibilities: \n \n Design and support automated testing frameworks for backend applications \n Develop and maintain test scripts using Python3 and pytest \n Implement and validate REST API ...

Senior Backend TypeScript Engineer Node.js, AWS Lambda, SQS, SNS

Hiring Organisation
Smart Sourcer Limited
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
From £700 to £800 per day
Overview: Youll operate as the technical spearhead for a greenfield product build, reporting to the Director of Engineering. Expect deep backend engineering, distributed system design, and high-quality serverless delivery, plus the chance to adopt modern AI-assisted development practices as part of your workflow. What Youll Bring: Senior … ability to architect and lead distributed REST microservices at scale. Strong authority in AWS serverless engineering: Lambda-first mindset, hands-on experience with API Gateway, SQS, Step Functions, EventBridge and IAM. Deep data expertise across Aurora MySQL and DynamoDB: schema design, access patterns, indexing, query tuning, and pragmatic ...

Senior Product Engineer (Hiring Immediately)

Hiring Organisation
17918
Location
Bermondsey, South East London, United Kingdom
senior, individual engineers have outsized impact which is exactly why ownership matters so much in this role. What you'll own Backend & architecture. Design, build and evolve the services, APIs, data pipelines and scoring/recommendation logic at the core of the product owning architecture, infrastructure, schema design … looking for Must-haves Strong full-stack/backend engineering. 5+ years of professional software development (stack flexible) with strong server-side fundamentals API design, data modelling/schema design, authentication patterns and clean service architecture. Comfortable across SQL databases and a modern backend stack (e.g. Python ...

Software Engineer III (UI) - Digital Markets Execution Technology (DMET), Execute

Hiring Organisation
17918
Location
Charing Cross, West End, United Kingdom
overview below carefully. JOB DESCRIPTION As a Software Engineer III at JPMorganChase, you serve as a seasoned member of an agile team to design and deliver trusted market-leading technology products in a secure, stable, and scalable way. You are responsible for carrying out critical technology solutions across multiple … Your success will be measured by resiliency, usability, and speed of delivery in a highly operational, business-critical environment. Job Responsibilities Executes software solutions, design, development, and technical troubleshooting with ability to think beyond routine or conventional approaches to build solutions or breakdown technical problems Creates secure and high ...

Software Engineer III (UI) - Digital Markets Execution Technology (DMET), Execute

Hiring Organisation
17918
Location
Charing Cross, South West London, United Kingdom
overview below carefully. JOB DESCRIPTION As a Software Engineer III at JPMorganChase, you serve as a seasoned member of an agile team to design and deliver trusted market-leading technology products in a secure, stable, and scalable way. You are responsible for carrying out critical technology solutions across multiple … Your success will be measured by resiliency, usability, and speed of delivery in a highly operational, business-critical environment. Job Responsibilities Executes software solutions, design, development, and technical troubleshooting with ability to think beyond routine or conventional approaches to build solutions or breakdown technical problems Creates secure and high ...

Senior Application Security Engineer - DevSecOps & Cloud Security

Hiring Organisation
Additional Resources
Location
London, United Kingdom
Employment Type
Permanent
Salary
£70000 - £80000/annum
applications, platforms and deployment processes. This is not a traditional vulnerability management role, it is a hands-on Application Security role centred on secure design, CI/CD security, cloud-native technologies, Kubernetes, API security, code analysis, security-as-code and supporting development teams to build secure applications. … controls throughout CI/CD pipelines. Strengthening the security of GitHub Actions and comparable continuous integration and deployment platforms. Providing technical guidance on secure API design and protecting externally accessible systems. Supporting the security of Azure cloud infrastructure, including Azure Kubernetes Service (AKS). Assisting with the protection ...

Engineering Lead, Scale

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
foundational systems that power our embedded finance platform at global scale. The team owns multi‐tenant infrastructure, drives cross‐domain product capabilities, and helps design technical solutions for enterprise customers. Key areas of ownership include: Embedded Finance Platform: Build and maintain the infrastructure powering customers like Rippling, Navan, Qantas … career development. Set technical direction for scalable, reliable backend systems and partner with senior engineers on architecture and design. Ensure high standards for system design, code quality, testing, and operational excellence. Drive improvements across reliability, observability, security, and developer productivity. Work cross‐functionally with product, design, compliance, sales ...

Dell Boomi Integration Consultant

Hiring Organisation
Oscar Associates (UK) Limited
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
£500 - £550 per day
Boomi AtomSphere, connecting multiple enterprise platforms across cloud and on-premise environments. This is a hands-on technical position requiring strong Boomi development experience, API integration knowledge and the ability to support complex integration landscapes. Key Responsibilities: Design and develop scalable integration solutions using Dell Boomi AtomSphere, including … secure Managed File Transfer (MFT) workflows to support high-volume and sensitive data transfers Publish, secure and govern REST/SOAP APIs through Boomi API Management, including gateway configuration, throttling and developer portal management Develop and maintain CI/CD pipelines using Git, Azure DevOps or Jenkins, supporting automated ...

Tech Lead / Senior Software Engineer / Software Architect

Hiring Organisation
Intec Select Ltd
Location
London, Portsoken, United Kingdom
Employment Type
Permanent
Salary
£80000 - £110000/annum
Tech Lead, Senior Software Engineer or Software Architect who enjoys solving complex technical problems and building modern, scalable software. Role & Responsibilities Lead the technical design and evolution of a large-scale business-critical platform. Improve the existing architecture and define a pragmatic roadmap towards a modern, scalable solution. Design … powered capabilities into the product to improve functionality and user experience. Drive the adoption of AI-assisted software development tools and engineering best practices. Design integrations with enterprise platforms, APIs and wider business systems. Work closely with Product, Architecture and Engineering teams to deliver incremental improvements. Mentor developers ...

Full Stack Developer

Hiring Organisation
Robert Half Limited
Location
London, United Kingdom
Employment Type
Contract, Work From Home
this is an opportunity to help shape the future of a rapidly evolving platform. Role The Full Stack Developer will contribute to full-stack design and development across the platform. Design, develop, and maintain both front-end user interfaces and back-end services, APIs, and databases. Monitor platform … strong focus on backend development. Bachelor's or Master's degree in Computer Science, Engineering, or a related discipline. Strong understanding of database design, data modelling, and optimisation, particularly using SQL. Hands-on experience working with Google Cloud Platform (GCP) services. Experience monitoring production systems, triaging issues, and distinguishing ...

Senior Python Backend Engineer Fully Remote, UK

Hiring Organisation
Interact Consulting Limited
Location
South West London, London, United Kingdom
Employment Type
Permanent, Work From Home
enjoys building from the ground up. The salary range is up to £120,000 depending on experience and fit. Key Responsibilities Own the design, development, and operation of the core backend services that power our consumer-facing products and internal operational tooling. Build scalable, low-latency systems that … notification preferences, audience segmentation, and delivery tracking. Integrate with third-party data providers and external services, ensuring robust failure handling, observability, and system resilience. Design and support secure internal tooling APIs, including role-based access controls, audit trails, change history, and safe administrative workflows. Build and operate event-driven ...

C# .Net Developer

Hiring Organisation
Pontoon
Location
Bromley, Kent, England, United Kingdom
Employment Type
Contractor
Contract Rate
£700 - £750 per day
Chicago). The role offers the opportunity to contribute to business-critical systems while working in a collaborative and supportive environment. Key Responsibilities Design, develop, enhance, and maintain enterprise applications using C# and .NET technologies. Support and improve existing business-critical systems, ensuring stability, performance, and scalability. Work closely … with business users, analysts, and technical teams to gather requirements and deliver solutions. Participate in the full software development lifecycle, including design, development, testing, deployment, and support. Collaborate with globally distributed development teams across multiple locations and time zones. Contribute to technical discussions, solution design, code reviews ...

C# .NET Developer

Hiring Organisation
Pontoon
Location
Bromley, London, South Yorkshire, United Kingdom
Employment Type
Contract
Contract Rate
£650 - £750/day Inside IR35
Chicago). The role offers the opportunity to contribute to business-critical systems while working in a collaborative and supportive environment. Key Responsibilities Design, develop, enhance, and maintain enterprise applications using C# and .NET technologies. Support and improve existing business-critical systems, ensuring stability, performance, and scalability. Work closely … with business users, analysts, and technical teams to gather requirements and deliver solutions. Participate in the full software development lifecycle, including design, development, testing, deployment, and support. Collaborate with globally distributed development teams across multiple locations and time zones. Contribute to technical discussions, solution design, code reviews ...

Software Engineer III

Hiring Organisation
RX Global
Location
Greater London, United Kingdom
Employment Type
Full Time
.NET/C#,, NET Core and familiarity with SQL or data skills Proficiency in Front end tech stack React or Angular Understanding of system design, domain modelling, and API design principles Experience writing unit and integration tests and working with CI/CD pipelines Exposure to cloud ...

UI Senior Lead Software Engineer - Commodities

Hiring Organisation
17918
Location
Charing Cross, West End, United Kingdom
inclusive team culture. This role emphasizes engineering excellence, operational readiness, and secure, compliant delivery in a fast-paced global environment. Job Responsibilities Lead the design and delivery of user interface capabilities across Execute, from discovery to production support Set front-end technical direction, including architecture, standards, performance, and testing … leadership in setting standards, leading designs, and directly managing or mentoring small teams of mid-level engineers Solid software engineering fundamentals, including OO/design patterns, debugging, and documentation Familiarity with agentic development approaches across the software development lifecycle Strong communication and people skills, with the ability to work ...

UI Senior Lead Software Engineer - Commodities

Hiring Organisation
17918
Location
Charing Cross, South West London, United Kingdom
inclusive team culture. This role emphasizes engineering excellence, operational readiness, and secure, compliant delivery in a fast-paced global environment. Job Responsibilities Lead the design and delivery of user interface capabilities across Execute, from discovery to production support Set front-end technical direction, including architecture, standards, performance, and testing … leadership in setting standards, leading designs, and directly managing or mentoring small teams of mid-level engineers Solid software engineering fundamentals, including OO/design patterns, debugging, and documentation Familiarity with agentic development approaches across the software development lifecycle Strong communication and people skills, with the ability to work ...

Director, Forward Deployed Engineering

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
lead a team of elite engineers who embed directly with Fortune 500 customers to ship deeply integrated AI agents—owning everything from agent design and evaluation to the backend services, data systems, and cloud infrastructure that make them production-ready. You'll partner closely with our Forward Deployed … volume for senior engineering roles. Hands‐on fluency with the full AI stack. Deep familiarity with LLMs and agent systems, evaluation frameworks, backend and API design (Python or TypeScript), data systems (PostgreSQL, DynamoDB, MongoDB, or similar), and cloud infrastructure (AWS, Azure, or GCP) including Kubernetes, Docker ...

Lead Software Engineer

Hiring Organisation
Intec Select Ltd
Location
London, Billingsgate, United Kingdom
Employment Type
Permanent
Tech Lead, Senior Software Engineer or Software Architect who enjoys solving complex technical problems and building modern, scalable software. Role & Responsibilities Lead the technical design and evolution of a large-scale business-critical platform. Improve the existing architecture and define a pragmatic roadmap towards a modern, scalable solution. Design … powered capabilities into the product to improve functionality and user experience. Drive the adoption of AI-assisted software development tools and engineering best practices. Design integrations with enterprise platforms, APIs and wider business systems. Work closely with Product, Architecture and Engineering teams to deliver incremental improvements. Mentor developers ...

Lead Software Engineer (UI) - Digital Markets Execution Technology (DMET), Execute

Hiring Organisation
J.P. Morgan
Location
London, UK
Employment Type
Full-time
This role emphasizes engineering excellence, operational readiness, and secure, compliant delivery in a fast-paced global environment. \n Job Responsibilities \n \n Lead the design and delivery of user interface capabilities across Execute, from discovery to production support \n Set front-end technical direction, including architecture, standards, performance … data-intensive user experiences \n Demonstrated technical leadership in setting standards, leading designs, and mentoring teams \n Solid software engineering fundamentals, including OO/design patterns, debugging, and documentation \n Familiarity with agentic development approaches across the software development lifecycle \n Strong communication skills and ability to work effectively ...

Junior FullStack Developer

Hiring Organisation
Randstad Technologies Recruitment
Location
London, United Kingdom
Employment Type
Permanent
Salary
£40000 - £45000/annum
features-you will be building impactful, user-facing applications from day one. Working closely with the founding team, you will help architect robust APIs, design intuitive frontend interfaces, and integrate cutting-edge AI/ML models into our core product. Qualifications & Experience Essential: 0-2 years of hands … projects). Education: A degree in Computer Science, Information Technology, or a related discipline. Core Fundamentals: A solid grounding in web development fundamentals, REST API design, and secure coding practices. Frontend: Proficiency in React and TypeScript, with a clear sense of how to build maintainable component hierarchies. Backend ...

Software Development Engineer III

Hiring Organisation
17918
Location
Charing Cross, West End, United Kingdom
technical leadership by designing shared GenAI capabilities, supporting live systems and raising engineering and AI delivery standards across the team through mentoring and rigorous design practice. Data & AI Product Development: Take ideas from discovery through rapid prototypes to production grade solutions that combine data, user facing applications and backend … services. Work closely with product managers, designers, data science and engineering teams to translate business needs into well designed technical solutions. Design and deliver LLM based applications and AI agents that enable intelligent decision making and automation, applying pragmatic engineering patterns and appropriate guardrails. Design and consume APIs ...

Software Development Engineer III

Hiring Organisation
17918
Location
Charing Cross, South West London, United Kingdom
technical leadership by designing shared GenAI capabilities, supporting live systems and raising engineering and AI delivery standards across the team through mentoring and rigorous design practice. Data & AI Product Development: Take ideas from discovery through rapid prototypes to production grade solutions that combine data, user facing applications and backend … services. Work closely with product managers, designers, data science and engineering teams to translate business needs into well designed technical solutions. Design and deliver LLM based applications and AI agents that enable intelligent decision making and automation, applying pragmatic engineering patterns and appropriate guardrails. Design and consume APIs ...

Back End Development Lead

Hiring Organisation
Oyster Consultants
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£60,000 - £75,000 per annum
evolve our stack and make constant improvements. Required Skills/Experience Strong C# development experience Experience with both .NET Core and .NET Web API Experience of building Microservices in .Net Core Experience using Message Based Architectures Experience using both SQL & NoSQL technologies Experience of API design Cloud ...

Machine Learning Engineer

Hiring Organisation
17918
Location
Charing Cross, West End, United Kingdom
pipelines using Python and common ML and DL libraries (e.g. Pytorch, Tensorflow) from early conceptualisation to full deployment in scalable production environments Ability to design, deploy and maintain ML solutions on modern frameworks to meet functional business requirements, adhering to software engineering best practices and with exposure to version … control, testing, MLOps, CI/CD and API design Hands on experience in using one of 3 major cloud technologies (AWS, Azure or GCP) in a production environment, as well as ML platforms (e.g., AWS Sagemaker, Azure Machine Learning studio) Be a lifelong learner and can demonstrate ...