API Design Jobs in London

26 to 50 of 61 API Design Jobs in London

Senior Full Stack Engineer

london, south east england, united kingdom
Hybrid / WFH Options
Ocean Orchestra
reflects the great diversity of our real customers and users across the world. What You’ll Do Own our engineering stack from MVP to scale — backend, frontend, infra . Design architecture, choose tools, and set engineering standards. Work directly with early users to iterate quickly. Collaborate with the founding team on strategy, hiring, and scaling the tech team. Ship … high-quality, user-focused features (that change Oceans and planet) fast. What We’re Looking For 5+ years of backend expertise in Go including API design, microservices architecture, gRPC/REST services, and database design (PostgreSQL, Redis). Frontend proficiency with React/Next.js, responsive design, and modern JavaScript/TypeScript Cloud infrastructure knowledge including AWS … and opportunity. Expert in solving deep technical problems with customer outcomes top of mind. Ability to evaluate and make decisions based on a balanced assessment of key factors, including design, scalability, performance, technical debt and cost efficiency. Working highly collaboratively in a team environment. What We Offer Professional Impact & Growth Build a high-impact platform from emerging MVP to More ❯
Posted:

Senior Full Stack Engineer

london (city of london), south east england, united kingdom
Hybrid / WFH Options
Ocean Orchestra
reflects the great diversity of our real customers and users across the world. What You’ll Do Own our engineering stack from MVP to scale — backend, frontend, infra . Design architecture, choose tools, and set engineering standards. Work directly with early users to iterate quickly. Collaborate with the founding team on strategy, hiring, and scaling the tech team. Ship … high-quality, user-focused features (that change Oceans and planet) fast. What We’re Looking For 5+ years of backend expertise in Go including API design, microservices architecture, gRPC/REST services, and database design (PostgreSQL, Redis). Frontend proficiency with React/Next.js, responsive design, and modern JavaScript/TypeScript Cloud infrastructure knowledge including AWS … and opportunity. Expert in solving deep technical problems with customer outcomes top of mind. Ability to evaluate and make decisions based on a balanced assessment of key factors, including design, scalability, performance, technical debt and cost efficiency. Working highly collaboratively in a team environment. What We Offer Professional Impact & Growth Build a high-impact platform from emerging MVP to More ❯
Posted:

Senior Software Engineer - Unified Client Experience (UCX)

City of London, London, United Kingdom
Hybrid / WFH Options
Hargreaves Lansdown
generation Unified Client Experience (UCX) frontend that will streamline client journeys across a range of products and services, in both web and mobile domains. It's an opportunity to design, architect and build a modern frontend using latest technologies and best practices to transform our savings and investment platform. The UCX team consolidates the efforts of the whole organisation … scale, regulated environments - ideally in Investment, Asset or Wealth Management. Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services. Experience in Java and Spring Boot, or iOS (Swift) or Android (Kotlin) along with exposure to Figma and Vercel is a big plus. Capable More ❯
Employment Type: Permanent, Work From Home
Salary: £95,000
Posted:

Senior Machine Learning Engineer London, United Kingdom

London, United Kingdom
PhysicsX Ltd
and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations - empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive. Note: We are currently recruiting … career goals. What you will do Work closely with our simulation engineers, data scientists and customers to develop an understanding of the physics and engineering challenges we are solving Design, build and test data pipelines for machine learning that are reliable, scalable and easily deployable Explore and manipulate 3D point cloud & mesh data Own the delivery of technical workstreams … Create analytics environments and resources in the cloud or on premise, spanning data engineering and science Identify the best libraries, frameworks and tools for a given task, make product design decisions to set us up for success Work at the intersection of data science and software engineering to translate the results of our R&D and projects into re More ❯
Employment Type: Permanent
Salary: GBP Annual
Posted:

Principal Software Engineer - Unified Client Experience (UCX)

City of London, London, United Kingdom
Hybrid / WFH Options
Hargreaves Lansdown
generation Unified Client Experience (UCX) frontend that will streamline client journeys across a range of products and services, in both web and mobile domains. It's an opportunity to design, architect and build a modern frontend using latest technologies and best practices to transform our savings and investment platform. The UCX team consolidates the efforts of the whole organisation … scale, regulated environments - ideally in Investment, Asset or Wealth Management. Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services. Experience in Java and Spring Boot, or iOS (Swift) or Android (Kotlin) along with exposure to Figma and Vercel is a big plus. Capable More ❯
Employment Type: Permanent, Work From Home
Salary: £10,000
Posted:

Software Engineering Manager - Unified Client Experience (UCX)

City of London, London, United Kingdom
Hybrid / WFH Options
Hargreaves Lansdown
generation Unified Client Experience (UCX) frontend that will streamline client journeys across a range of products and services, in both web and mobile domains. It's an opportunity to design, architect and build a modern frontend using latest technologies and best practices to transform our savings and investment platform. The UCX team consolidates the efforts of the whole organisation … scale, regulated environments - ideally in Investment, Asset or Wealth Management. Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services. Experience in Java and Spring Boot, or iOS (Swift) or Android (Kotlin) along with exposure to Figma and Vercel is a big plus. Capable More ❯
Employment Type: Permanent, Work From Home
Posted:

.Net developer

London, South East, England, United Kingdom
eTeam Inc
every year of education • At least 8-10 years of experience with Information Technology Key Responsibilities • Develop and maintain enterprise-scale .NET applications using ASP.NET Core 9.0 and C# • Design and implement RESTful APIs for biogas trading, inventory management, and regulatory reporting • Build complex business logic for RINS credit calculations, LCFS compliance, and carbon credit trading • Work with PostgreSQL … and Microsoft Identity Platform • Develop email workflow systems and automated reporting for regulatory compliance • Create scheduled background jobs using Quartz.NET for data processing and calculations • Integrate with Microsoft Graph API for SharePoint document management via Azure MS Graph • Build real-time features using SignalR for live trading updates • Implement data validation using FluentValidation • Work with Docker and OpenShift for … containerized deployments Required Technical Skills • 5+ years of experience with .NET development (C#, ASP.NET Core) • Strong experience with Entity Framework Core and PostgreSQL • Proficiency in RESTful API design and OpenAPI/Swagger documentation • Experience with authentication systems (OAuth2, JWT, Azure AD) • Knowledge of containerization (Docker) and Kubernetes/OpenShift • Experience with background job processing and scheduled tasks • Understanding More ❯
Employment Type: Contractor
Rate: £280 - £297 per day
Posted:

Staff Software Engineer - AI/ML

City of London, London, United Kingdom
Hybrid / WFH Options
SR2 | Socially Responsible Recruitment | Certified B Corporation™
influence: you’ll own the internal AI stack, mentor other engineers, and help define how AI and automation are adopted across the company. What You’ll Do Lead the design, architecture, and implementation of internal AI/ML systems for business intelligence. Build robust APIs, microservices, and data pipelines to power intelligent, data-driven tools. Develop retrieval-augmented generation … in Python plus at least one other backend language (TypeScript or Java preferred). Proven experience with AWS , containerisation, and infrastructure as code (Terraform, Docker). Solid understanding of API design, data modelling, and microservice architecture. Excellent communication skills, with the ability to translate technical outcomes into business impact. Tech Environment Languages: Python, TypeScript, Java AI/LLM More ❯
Posted:

Staff Software Engineer - AI/ML

london, south east england, united kingdom
Hybrid / WFH Options
SR2 | Socially Responsible Recruitment | Certified B Corporation™
influence: you’ll own the internal AI stack, mentor other engineers, and help define how AI and automation are adopted across the company. What You’ll Do Lead the design, architecture, and implementation of internal AI/ML systems for business intelligence. Build robust APIs, microservices, and data pipelines to power intelligent, data-driven tools. Develop retrieval-augmented generation … in Python plus at least one other backend language (TypeScript or Java preferred). Proven experience with AWS , containerisation, and infrastructure as code (Terraform, Docker). Solid understanding of API design, data modelling, and microservice architecture. Excellent communication skills, with the ability to translate technical outcomes into business impact. Tech Environment Languages: Python, TypeScript, Java AI/LLM More ❯
Posted:

Staff Software Engineer - AI/ML

london (city of london), south east england, united kingdom
Hybrid / WFH Options
SR2 | Socially Responsible Recruitment | Certified B Corporation™
influence: you’ll own the internal AI stack, mentor other engineers, and help define how AI and automation are adopted across the company. What You’ll Do Lead the design, architecture, and implementation of internal AI/ML systems for business intelligence. Build robust APIs, microservices, and data pipelines to power intelligent, data-driven tools. Develop retrieval-augmented generation … in Python plus at least one other backend language (TypeScript or Java preferred). Proven experience with AWS , containerisation, and infrastructure as code (Terraform, Docker). Solid understanding of API design, data modelling, and microservice architecture. Excellent communication skills, with the ability to translate technical outcomes into business impact. Tech Environment Languages: Python, TypeScript, Java AI/LLM More ❯
Posted:

Staff Software Engineer - AI/ML

London Area, United Kingdom
Hybrid / WFH Options
SR2 | Socially Responsible Recruitment | Certified B Corporation™
influence: you’ll own the internal AI stack, mentor other engineers, and help define how AI and automation are adopted across the company. What You’ll Do Lead the design, architecture, and implementation of internal AI/ML systems for business intelligence. Build robust APIs, microservices, and data pipelines to power intelligent, data-driven tools. Develop retrieval-augmented generation … in Python plus at least one other backend language (TypeScript or Java preferred). Proven experience with AWS , containerisation, and infrastructure as code (Terraform, Docker). Solid understanding of API design, data modelling, and microservice architecture. Excellent communication skills, with the ability to translate technical outcomes into business impact. Tech Environment Languages: Python, TypeScript, Java AI/LLM More ❯
Posted:

Technology Architech

London, South East, England, United Kingdom
Harrison Holgate
comprehensive architecture solutions that integrate core business platforms with wider enterprise systems. Establish and maintain architectural standards, best practices, and governance frameworks across the organisation. Assess existing systems and design strategies for optimisation, modernisation, and scalability. Partner with engineering, operations, security, and business teams to ensure technology solutions align with strategic objectives. Provide expert guidance on broking systems, API design, system integration, security frameworks, and user experience. Translate complex business needs into clear, implementable architectural designs. Ensure high availability, security, and performance across hybrid and cloud-based environments. Stay informed on emerging technologies and market developments relevant to the insurance industry. Skills & Experience Proven experience as a Technology Architect , Solutions Architect , or in a senior technology leadership … Experience designing and delivering systems integrations using APIs, middleware, and modern data exchange approaches. Understanding of enterprise architecture frameworks (e.g. TOGAF , Zachman ). Strong proficiency with Azure and contemporary design principles such as microservices and event-driven architecture. Excellent communication and stakeholder engagement skills across all levels. Familiarity with DevOps practices (CI/CD pipelines, monitoring, containerisation). Knowledge More ❯
Employment Type: Full-Time
Salary: £85,000 per annum
Posted:

Senior Software Engineer

EC2M, Bishopsgate, Greater London, United Kingdom
Retelligence
the Software Engineering group. In addition to contributing to feature development, you will play a role in shaping the technology and process strategies, and occasionally lead innovation or software design initiatives. Key Responsibilities: Develop new features with a strong focus on high-quality code. Conduct peer code reviews to ensure quality and adherence to best practices. Participate in daily … organization's objectives. Work closely with tech leads, engineers, testers, and other personnel to deliver high-quality products. Take ownership of initiatives related to innovation or addressing technical debt. Design, document, and communicate system solutions with a balanced focus on time, quality, cost, and performance. Collaborate with colleagues across the organization to gain buy-in and feedback on proposals … Required Knowledge & Experience: Essential: Strong proficiency in C# at a commercial level. Solid experience with .NET Core and related open-source technologies. Knowledge of Object Orientation, SOA, and relevant design patterns. Experience with modern software development practices, including agile methodologies , version control, code reviews, and continuous integration. Understanding of concurrency, asynchrony, and parallelism. Experience with Test Driven Development (TDD More ❯
Employment Type: Permanent
Salary: £80000 - £95000/annum + Bonus
Posted:

Java Software Engineer

London, South East, England, United Kingdom
Hybrid / WFH Options
Noir
and Spring Boot experience, solid understanding of Kubernetes and AWS services, and hands-on database development with SQL-based systems. Familiarity with mobile integrations (iOS/Android native), RESTful API design, and Agile delivery methodologies will be highly beneficial. This is an exciting opportunity to work in a dynamic FinTech environment where innovation, quality, and performance are at More ❯
Employment Type: Contractor
Rate: £400 - £420 per day
Posted:

Senior Java Application Engineer

London, South East, England, United Kingdom
FDM Group
Responsibilities Elevate code into the development, test, and production environments on schedule, providing follow up production support as well as developing Spring Boot microservices Provide senior level system analysis, design, development, and implementation of applications and databases Integrate third party products and submit change control requests as well as documents Create cucumber, playwright integration tests while deploying AWS infrastructure … Requirements Minimum of 5 years’ experience as a Senior Java Application Engineer/development experience Good understanding of Languages/Frameworks such as Java and Spring Experience with AWS, API Design, Automation testing, Cucumber and Playwright Strong analytical and problem-solving skill Ability to work in cross functional teams Familiarity with Git, Jenkins with experience working in agile More ❯
Employment Type: Contractor
Rate: £50,000 - £70,000 per annum
Posted:

Senior Full Stack Engineer

London, South East, England, United Kingdom
Harnham - Data & Analytics Recruitment
Experience deploying applications in cloud environments using containers and orchestration tools. Proficiency in the Python ecosystem for backend development and AI integration. Strong database knowledge (SQL and NoSQL) and API design/integration. Familiarity with CI/CD pipelines and modern DevOps workflows. Understanding of authentication, authorization, and web security best practices. Nice-to-haves: Experience deploying ML More ❯
Employment Type: Full-Time
Salary: £100,000 - £120,000 per annum
Posted:

Data Engineer

london, south east england, united kingdom
Hybrid / WFH Options
Stott and May
Engineer Location: London (flexible remote working available) Contract Duration: Until 31st December 2025 Day Rate: £340 (Inside IR35) The Role We are looking for a skilled Data Engineer to design, develop, and deliver high-quality applications that meet evolving business needs. You will work across the full software development lifecycle, ensuring code quality, security, and scalability, while collaborating with … both technical and non-technical stakeholders in an Agile environment. Key Responsibilities Design, develop, test, and deploy robust applications. Ensure adherence to coding standards, security, and best practices. Build and integrate APIs with CRM, SaaS, and third-party platforms. Work with TypeScript, , , and AWS services (Lambda, API Gateway). Contribute to Agile, cross-functional teams across the SDLC. … Communicate effectively with stakeholders at all levels. Essential Skills & Experience Proficiency in TypeScript, , Hands-on experience with AWS services (e.g., Lambda, API Gateway). Strong background in API design and integration. Excellent communication and collaboration skills. More ❯
Posted:

Software Engineer

London Area, United Kingdom
Hybrid / WFH Options
Venn Apps
products. Our stack includes React, TypeScript, Next.js, and Google Cloud Platform (GCP). You’ll collaborate closely with designers to create exceptional user experiences, and with platform engineers to design and implement serverless APIs and background services that scale globally. This is a fantastic opportunity to join a rapidly growing startup as we enter the next phase of expansion. … as a software engineer (or equivalent commercial experience) Strong knowledge of React, TypeScript, and Next.js Experience with GCP or another cloud provider (e.g. AWS, Firebase, or Azure) Understanding of API design and asynchronous data handling Familiarity with CI/CD workflows and version control (Git) Strong problem-solving skills and attention to detail Comfortable working in a fast More ❯
Posted:

Software Engineer

City of London, London, United Kingdom
Hybrid / WFH Options
Venn Apps
products. Our stack includes React, TypeScript, Next.js, and Google Cloud Platform (GCP). You’ll collaborate closely with designers to create exceptional user experiences, and with platform engineers to design and implement serverless APIs and background services that scale globally. This is a fantastic opportunity to join a rapidly growing startup as we enter the next phase of expansion. … as a software engineer (or equivalent commercial experience) Strong knowledge of React, TypeScript, and Next.js Experience with GCP or another cloud provider (e.g. AWS, Firebase, or Azure) Understanding of API design and asynchronous data handling Familiarity with CI/CD workflows and version control (Git) Strong problem-solving skills and attention to detail Comfortable working in a fast More ❯
Posted:

Software Engineer

london, south east england, united kingdom
Hybrid / WFH Options
Venn Apps
products. Our stack includes React, TypeScript, Next.js, and Google Cloud Platform (GCP). You’ll collaborate closely with designers to create exceptional user experiences, and with platform engineers to design and implement serverless APIs and background services that scale globally. This is a fantastic opportunity to join a rapidly growing startup as we enter the next phase of expansion. … as a software engineer (or equivalent commercial experience) Strong knowledge of React, TypeScript, and Next.js Experience with GCP or another cloud provider (e.g. AWS, Firebase, or Azure) Understanding of API design and asynchronous data handling Familiarity with CI/CD workflows and version control (Git) Strong problem-solving skills and attention to detail Comfortable working in a fast More ❯
Posted:

Software Engineer

london (city of london), south east england, united kingdom
Hybrid / WFH Options
Venn Apps
products. Our stack includes React, TypeScript, Next.js, and Google Cloud Platform (GCP). You’ll collaborate closely with designers to create exceptional user experiences, and with platform engineers to design and implement serverless APIs and background services that scale globally. This is a fantastic opportunity to join a rapidly growing startup as we enter the next phase of expansion. … as a software engineer (or equivalent commercial experience) Strong knowledge of React, TypeScript, and Next.js Experience with GCP or another cloud provider (e.g. AWS, Firebase, or Azure) Understanding of API design and asynchronous data handling Familiarity with CI/CD workflows and version control (Git) Strong problem-solving skills and attention to detail Comfortable working in a fast More ❯
Posted:

eFX Software Engineer

London, South East, England, United Kingdom
Hybrid / WFH Options
Salt Search
and scalable solutions to support institutional trading platforms. Key Responsibilities: Develop and maintain low-latency eFX trading systems using high-performance Java (e.g., lock-free, low-GC techniques). Design and implement fault-tolerant system architectures with <40 microseconds one-way latency. Collaborate with cross-functional teams to define and evolve architecture and engineering practices. Influence technical strategy, ensuring … Familiarity with quantitative finance , algorithmic trading , and implementing controls in automated trading systems. Proven experience with DevOps , Agile methodologies , TDD , and use of CI/CD tools. Background in API design and automated testing frameworks. This is an excellent opportunity to work on complex, high-impact systems within a supportive and forward-thinking technology team. *Rates depend on More ❯
Employment Type: Full-Time
Salary: Salary negotiable
Posted:

Solutions Architect

London, South East, England, United Kingdom
FDM Group
This is initially a 6 month contract with the potential to extend and will be a hybrid role that will be based in either London or Coventry . Responsibilities: Design robust integration solutions across commercial, HR, and data platforms within a complex, multi-brand retail environment Lead architectural planning for the decommissioning of legacy systems, ensuring smooth transitions to … modern, scalable services Define and document integration standards, including API strategies, event schemas, and interface contracts to enable decoupled, reusable services Implement event-driven architectures using Kafka to support real-time data exchange and responsive system interactions Collaborate cross-functionally with product managers, engineering teams, and platform leads to define scalable service boundaries and integration touchpoints Support the design … adoption of strategic data services, promoting data integrity, consistency, and standardisation across the enterprise Ensure integration consistency in areas such as data handling, authentication, error management, and versioning Lead design reviews for integration solutions, ensuring alignment with enterprise architecture principles and governance frameworks Act as a trusted advisor, championing best practices in integration architecture and guiding teams on modern More ❯
Employment Type: Contractor
Rate: £65,000 - £80,000 per annum
Posted:

Full Stack Software Engineer

London, United Kingdom
Hybrid / WFH Options
Circle Group
to £90,000 per annum, depending on experience Location: fully remote, with occasional visits to Basingstoke We are looking for a skilled Full Stack Software Engineer to design and develop cutting-edge products with a focus on Python , PostgreSQL and front-end development. You'd be working in a flexible, remote-first environment, tackling interesting and complex challenges within … visits to Basingstoke as needed. Qualifications & Skills required: 5+ years of Python development Strong understanding of database systems (e.g. PostgreSQL) 5+ years of front-end development and deployment RESTful API design and development Demonstrable clean, maintainable code practices What you'd be doing: Take ownership of designing and delivering new capabilities within existing systems Requirements gathering and programme More ❯
Employment Type: Permanent, Work From Home
Salary: £90,000
Posted:

Full Stack Software Engineer

London, South East, England, United Kingdom
Hybrid / WFH Options
Circle Recruitment
circa £80,000 to £90,000 per annum, depending on experienceLocation: fully remote, with occasional visits to Basingstoke We are looking for a skilled Full Stack Software Engineer to design and develop cutting-edge products with a focus on Python , PostgreSQL and front-end development. You'd be working in a flexible, remote-first environment, tackling interesting and complex … visits to Basingstoke as needed. Qualifications & Skills required: 5+ years of Python development Strong understanding of database systems (e.g. PostgreSQL) 5+ years of front-end development and deployment RESTful API design and development Demonstrable clean, maintainable code practices What you'd be doing: Take ownership of designing and delivering new capabilities within existing systems Requirements gathering and programme More ❯
Employment Type: Full-Time
Salary: £80,000 - £90,000 per annum, Inc benefits
Posted:
API Design
London
10th Percentile
£68,500
25th Percentile
£72,500
Median
£85,000
75th Percentile
£108,750
90th Percentile
£130,000