26 to 50 of 55 API Design Jobs in London

Software Engineer

Hiring Organisation
NearTech Search
Location
City of London, London, United Kingdom
agility with the backing of a well-established business. The Senior Back End Developer will... take ownership of backend engineering for a new API-first data intelligence platform. Role Highlights Design and build scalable backend systems from a true greenfield starting point Define architecture, balancing rapid delivery with … long-term scalability Develop API-first services for data-heavy, enterprise-grade applications Embed observability, metrics, and performance tracking from day one Collaborate within a small, high-autonomy team shaping a new product You Will Need Extensive backend development experience within data-driven B2B environments Strong programming skills ...

Full Stack Developer .NET React

Hiring Organisation
Young's Employment Services Ltd
Location
West London, London, United Kingdom
Employment Type
Permanent, Work From Home
Salary
£80,000
deployment, Azure Service Bus, Blob Storage SQL Server T-SQL, EF Core migrations, query optimisation Azure DevOps Repos, Boards, Pipelines, Test Plans REST API design and OpenAPI/Swagger documentation This is an exciting time to be joining our client with salary will be based on experience ...

Principal Engineer

Hiring Organisation
Arrive
Location
City Of London, England, United Kingdom
technical initiatives across multiple teams Experience designing scalable, high-performance systems Experience working with legacy or monolithic systems and modernising them Strong understanding of API design and distributed systems Knowledge of modern engineering practices, including CI/CD and DevSecOps Understanding of secure development practices such as OWASP ...

Junior Back-end Engineer

Hiring Organisation
ivee
Location
City of London, London, United Kingdom
maintain server-side logic using modern backend frameworks (e.g. Node.js, Python, Go) Work with APIs — designing, integrating, and maintaining RESTful endpoints Support database design and optimisation (e.g. PostgreSQL, MongoDB) Collaborate with front-end and product teams to deliver full-stack features Write clean, testable, and maintainable code Help improve ...

Senior Full Stack Engineer

Hiring Organisation
Access Computer Consulting
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
£400 - £440/day
This role is designed for engineers who have built and operated large-scale systems end-to-end, not those with superficial exposure or purely design-focused experience. Candidates must have strong experience of Java Full Stack, React, Kubernetes & Docker. Experience in building responsive, component based user interfaces using modern … front end frameworks. Hands on expertise in API design and development (REST/JSON), including versioning and backward compatibility. Experience with UI testing, component testing, and front end build tooling. Experience in CI/CD pipelines, GitOps workflows, A/B testing strategies and also automating the workflows ...

Chief Technology Officer (CTO) at Telehealth Platform

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
such as AWS, Google Cloud, or Azure and DevOps practices Knowledge of healthcare data privacy standards including GDPR and HIPAA compliance Skilled in architecture design for scalable, secure, and reliable systems Experience managing real‐time communication technologies like WebRTC and video consultation infrastructure Platform & Development Proficiency with modern … frameworks (React, Node.js, Next.js) and mobile development platforms (iOS, Android, React Native, Flutter) Familiarity with API design, microservices, and payment integration systems (e.g., Stripe) Leadership & Strategic Qualities 10+ years experience in software engineering with at least 5 years in senior technical leadership roles Demonstrated ability to build ...

Full Stack Engineer

Hiring Organisation
Humanoid
Location
London Area, United Kingdom
create the world’s leading, commercially scalable, safe, and advanced humanoid robots that seamlessly integrate into daily life and amplify human capacity. Responsibilities Design and implement a centralized cloud-based platform for managing a fleet of humanoid robots, monitoring system health, and visualizing fleet-level KPIs Develop robust backend … Expertise Proficiency in one of Python, Javascript, Golang or Rust Familiarity with React (or similar frameworks) for creating user-friendly web applications. Expertise in API design, data modeling, and distributed architectures Proficiency with CI/CD pipelines, containerization (e.g., Docker, Kubernetes), and workflow automation. Proficiency in infrastructure ...

Pricing & Market Data (Migration Specialist)

Hiring Organisation
HCLTech
Location
City of London, London, United Kingdom
Trading (Oil, Gas, or Power). Technology Stack : Deep Mastery: Gresham Asset Control (legacy) and Prime EDM. Architecture : Cloud-native migrations (AWS/Azure), API design, and SQL/NoSQL performance tuning. Scripting : Python (preferred) or Java for custom business logic and automation. Pricing Logic : Strong understanding ...

Senior Backend Engineer

Hiring Organisation
Searchability®
Location
London Area, United Kingdom
Experience working on the engineering team in a start-up, scale-up or product-driven company Strong understanding and experience with building and consuming API-driven solutions. Experience with database technologies, cloud platforms (e.g., AWS, Azure, GCP), and API design principles. A minimum of a Bachelor ...

Back End Developer

Hiring Organisation
Albert Bow
Location
London Area, United Kingdom
+ mobile applications Building and maintaining high‐performance APIs and distributed microservices Solving problems around scalability, reliability, security, and automation Working with modern API protocols including GraphQL and gRPC Enhancing the platform that connects both traditional and on‐chain financial services Must‐have experience: Strong backend engineering background with …/or Golang Solid understanding of microservices, event‐driven systems & distributed architecture Strong knowledge of PostgreSQL and/or Redis Understanding of web semantics, API design & backend web standards Proficiency with Git and version control workflows Experience with CI/CD, build automation and modern engineering pipelines Excellent ...

Mid-Senior Ruby on Rails Engineer (B2B SaaS | Hybrid | UK)

Hiring Organisation
Transreport
Location
London Area, United Kingdom
architecture Extensive experience with PostgreSQL, including performance tuning and complex queries. Experience with background job processing using Sidekiq and Redis. Solid understanding of RESTful API design, JSON serialization, and authentication (e.g., JWT, SSO). Hands-on experience with AWS services and containerised deployments (Docker). Experience troubleshooting ...

AI Platform Engineer

Hiring Organisation
The Portfolio Group
Location
London, Castle Baynard, United Kingdom
Employment Type
Permanent
Salary
£75000 - £85000/annum
owning the cloud-native platform that underpins conversational AI and generative AI products at scale. Sitting at the core of AI delivery, you will design, build, and operate the runtime, infrastructure, and operational layers supporting RAG pipelines, LLM orchestration, vector search, and evaluation workflows across AWS and Databricks. Working … platform powering conversational assistants and generative AI products. Build, operate, and optimise RAG and LLM-backed services, improving latency, reliability, and cost. Design and run cloud-native AI services across AWS and Databricks, including ingestion and embedding pipelines. Scale and operate vector search infrastructure (Weaviate, OpenSearch, Algolia, AWS Bedrock ...

Product Engineer

Hiring Organisation
Affinity Labs
Location
London Area, United Kingdom
full-stack product delivery, from infrastructure and AI integrations through to React/React Native interfaces, collaborating closely with founders, creators, product, and design to turn lean specs into scalable, user-loved software. We’re looking for a strong generalist with backend depth and real mobile experience. Responsibilities Implement … mobile + web frontend → APIs → data models → integrations) while maintaining quality and velocity. Build React Native mobile apps and shared component systems across products. Design and ship scalable backend services (APIs, integrations, AI workflows). Run tight build → test → iterate → ship loops; provide realistic estimates and surface blockers early. ...

Lead Full Stack Developer

Hiring Organisation
G.R.E. Recruitment Limited
Location
City of London, London, United Kingdom
Employment Type
Permanent, Work From Home
Salary
£95,000
Start Up - Smart Living Platform Fully Remote - Must be UK based £85,000 - £95,000 + Stock Options (DOE) Essential Exp: Laravel, Flutter, SaaS, API Design, MySQL/PostgreSQL/MariaDB G.R.E. Recruitment is DELIGHTED and EXCITED to partner with an exciting UK based PropTech Start-Up company … defining technical standards, scalability strategy, and product direction across the technical ecosystem. In this role you will: Own and evolve a Laravel-based REST API Develop and maintain a Flutter mobile application (iOS & Android) Design and implement secure, multi-tenant architecture Establish clean coding standards and engineering best ...

Backend Software Engineer (Python)

Hiring Organisation
SR2 | Socially Responsible Recruitment | Certified B Corporation™
Location
City of London, London, United Kingdom
engineering hires, you will play a key role in building and scaling the core platform , working closely with the CTO and senior engineers to design, develop and deploy new features. This is a hands-on role with real ownership and impact on product direction. Requirements 2+ years of commercial … production web applications (not just data science scripts) Experience with Docker and containerised applications Experience working with relational databases (e.g. PostgreSQL) Good understanding of API design and backend architecture Proficiency with Git Willingness to work 2 days per week onsite in London Nice to have Exposure ...

Principal Engineer

Hiring Organisation
Omnis Partners
Location
City of London, London, United Kingdom
exclusively partnered with a fast-scaling AI startup redefining how enterprises turn AI strategy into production-ready systems. Their platform enables organisations to design, deploy, and manage AI agents at scale and they’re now hiring a Principal Engineer to take ownership of the technical vision. This … decisions, setting engineering direction, and building with clarity and purpose. You’ll act as the technical cornerstone of the organisation. 🧠 Key Responsibilities Lead the design and evolution of architecture across frontend, backend, AI orchestration, and infrastructure. Establish engineering principles that optimise for speed, quality, and scalability. Own key decisions ...

Ruby Developer

Hiring Organisation
Proactive Appointments
Location
London, United Kingdom
Employment Type
Permanent
Salary
GBP 70,000 - 80,000 Annual
develop new features, enhance existing systems, and ensure our platform remains stable and efficient. Your deep understanding of Rails architecture, PostgreSQL optimisation, and API design will be essential as you contribute to ongoing development projects. If you enjoy collaborating in Agile/Scrum environments, value clean code ...

Principal Java Engineer

Hiring Organisation
Fynity
Location
London Area, United Kingdom
senior individual-contributor role within a high-performing engineering team, building asynchronous, message-driven systems designed for scale, resilience, and near-zero downtime. Design and implement high-throughput, low-latency systems processing millions of real-time payment events Build event-driven architectures using modern Java and reactive frameworks Work … extensively with non-blocking I/O, asynchronous flows, back-pressure, and concurrency Contribute to system and API design, focusing on scalability, fault tolerance, and observability Collaborate closely with architects, engineers, and client teams across Europe Operate in Agile environments (Scrum/Kanban) with a strong engineering culture ...

Ruby on Rails Backend Engineer

Hiring Organisation
Rise Technical Recruitment
Location
Fulham, London, United Kingdom
Employment Type
Permanent
Salary
£60000 - £80000/annum Private Healthcare + Holiday + Pensi
evolution of core Ruby on Rails operational platforms. Optimise PostgreSQL performance and Sidekiq background job efficiency. Manage secure third-party integrations and RESTful API design. Partner with Platform teams on AWS and CI/CD reliability. The Person: Deep experience with Ruby on Rails and OOP. Expert in PostgreSQL ...

Enterprise Architect – Product Inventory Domain

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
technology and business strategy. You will work with the business on ideation and discovery for key strategic Commercial initiatives and provide high level solution design for those initiatives. The role involves collaboration with domain solution architects and the wider architecture team, all reporting to the Head of Architecture. … technology landscape, identifying patterns and standards, and ensuring artefacts and decisions are well documented and governed. Key Skills & Qualifications Experience of pragmatic architecture governance, design governance, production of enterprise artefacts, and maintenance of architecture viewpoints. Demonstrable experience leading major initiative discovery and experimentation. Demonstrable experience designing high-quality software ...

iOS Developer

Hiring Organisation
Expedia Group
Location
City of London, London, United Kingdom
architectural direction, influencing engineering standards, and shaping the evolution of AI-enabled capabilities across the mobile platform. In this role, you will: Lead the design, development, and maintenance of advanced iOS applications, ensuring high performance, quality, and responsiveness across Expedia Group’s product suite. Architect and implement robust, scalable … system and API designs, including effective data modelling to support complex business requirements. Drive cross-functional collaboration to define, develop, and ship impactful features, ensuring alignment with organisational goals and technical strategy. Champion best practices in software engineering, testability, and maintainability through code reviews and mentoring. Safely integrate ...

Software Engineer — Full Stack & Cloud

Hiring Organisation
upLYFT
Location
London, England, United Kingdom
shipped real products before. What you will do Own and build core parts of the product stack across backend, cloud and application layers Design and implement scalable backend systems, APIs and infrastructure Work across web and mobile product surfaces, including integration with Android, iOS and web platforms Support deployment … experience is a strong plus Experience with cloud storage and compute Working knowledge of deployment pipelines and CI/CD Strong backend architecture and API design Experience working across web platforms Comfort working with mobile stacks, including Android and iOS integrations Familiarity with Kotlin, Java and iOS development ...

Senior Software Developer (Full Stack)

Hiring Organisation
Reed
Location
Holborn, London, England, United Kingdom
Employment Type
Full-Time
Salary
£80,000 - £95,000 per annum, Inc benefits
commercial software development experience. Proven success in high-performing engineering teams within fast-paced environments. Deep expertise in: Python (Django, Flask, or FastAPI) PostgreSQL (design, optimisation, maintenance) Containerisation (Docker/Kubernetes) Event-driven architecture (Kafka/RabbitMQ) Desirable experience includes: TypeScript/JavaScript (NextJS, NodeJS, Tailwind) Terraform and DevOps … practices Experience in building and scaling SaaS platforms in production. Strong background in software architecture, microservices, and API design. Hands-on experience with AWS platform. Excellent communication skills, capable of motivating and aligning technical teams. Experience with AI tools, APIs, or ML pipelines is highly desirable. Bonus: Exposure ...

Software Engineer

Hiring Organisation
NJF Global Holdings Ltd
Location
City of London, London, United Kingdom
client, a leading global trading firm, is seeking Software Engineers to join its R&D team. This team work to design and deliver both software and hardware solutions across networking, HPC and real time acceleration. The successful candidate will bring low-level engineering skills, networking and an understanding … software solutions that have a direct impact on trading performance. Key Responsibilities: Identify performance and architectural improvement opportunities within a large automated trading system. Design, develop, test, and deploy high-performance software solutions. Collaborate with development and operational teams to coordinate technology introduction and production rollout. Build internal productivity ...

Senior Android Engineer - Hybrid, £100K

Hiring Organisation
Oliver Bernard
Location
City of London, London, United Kingdom
share code with iOS. You’ll be joining a collaborative engineering group working on major new features, shaping technical discussions, influencing architecture and API design, and helping to evolve a category-defining product used across the UK, US and several new international markets launching in 2026. What they ...