26 to 50 of 78 API Design Jobs in London

Principal Technical Lead

Hiring Organisation
RAIL SAFETY AND STANDARDS BOARD
Location
London, UK
Employment Type
Full-time
delivery of the platform, ensuring the team consistently ships high-quality, production-ready increments. Ensure engineering standards are followed across the team: coding conventions, API design, security practices, and code review processes. Lead estimation, sprint planning, and decomposition of technical work; proactively identify and manage technical risk, dependencies … architecture function, clearly articulating technical constraints, risks, or emerging complexity with architectural implications, supported by evidence and proposed alternatives. Ensure application of secure-by-design principles and validate and refine Figma wireframes. Represent the team's technical work clearly and credibly to non-technical audiences. Define and enforce ...

Senior Software Engineer

Hiring Organisation
TRIA
Location
London Area, United Kingdom
code quality, and conduct structured code reviews across the delivery team. Work directly with the BA to translate business requirements into sound technical design and produce low-level design documentation. Make architecture decisions, present options clearly to non-technical stakeholders, and govern integration standards across the programme. Support … roles, with strong hands-on .NET/C# delivery. Demonstrable experience leading architecture decisions on production-grade systems, not just contributing to them. REST API design and integration experience at scale, including defining and governing integration standards. Microsoft SQL Server: schema design, query optimisation, and working knowledge ...

Lead .NET Engineer/Architect

Hiring Organisation
Tria
Location
City of London, London, United Kingdom
Employment Type
Permanent
Salary
£80000 - £100000/annum
code quality, and conduct structured code reviews across the delivery team. Work directly with the BA to translate business requirements into sound technical design and produce low-level design documentation. Make architecture decisions, present options clearly to non-technical stakeholders, and govern integration standards across the programme. Support … roles, with strong hands-on .NET/C# delivery. Demonstrable experience leading architecture decisions on production-grade systems, not just contributing to them. REST API design and integration experience at scale, including defining and governing integration standards. Microsoft SQL Server: schema design, query optimisation, and working knowledge ...

Senior Product Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
rather than hours. You ship these without needing to be guided step by step. You're not a specialist who hands off at the API boundary. You think in user outcomes and delivery units, and you're reliable: your code handles edge cases, your APIs have clean contracts … across the stack — ship workable React/TypeScript frontend for product features; not a frontend specialist, but comfortable and pragmatic Collaborate with product and design — translate ambiguous requirements into concrete shipped work; be the engineer who unblocks, not the one who waits Maintain quality at speed — handle data integrity ...

AI Platform/ DevOps Engineer

Hiring Organisation
The Portfolio Group
Location
City of London, London, Castle Baynard, United Kingdom
Employment Type
Permanent
Salary
£70000 - £80000/annum + Benefits
secure, and cost-efficient platform infrastructure that enables AI engineering teams to ship and operate AI products reliably in production. What you'll do Design, build, and operate cloud-native AI platform infrastructure across AWS (Lambda, API Gateway, DynamoDB, S3, CloudWatch) and Databricks Deploy and operate containerised services … workflows, and RAG components Implement observability across AI workloads using CloudWatch, MLflow, and OpenTelemetry - covering latency, throughput, cost, and system health Apply secure-by-design principles including IAM, encryption, network controls, and audit logging Work closely with AI engineers to translate prototypes and proof-of-concepts into production-ready ...

Full Stack Software Engineer

Hiring Organisation
Brio Digital
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
GBP 450 Daily
looking for two experienced Senior Full Stack Software Engineers to join a high-performing engineering team. You will play a senior role in the design and delivery of modern, scalable web applications, bringing strong full stack expertise across Next.js, TypeScript, and AWS in a programme delivering meaningful impact across … services nationwide. KEY RESPONSIBILITIES Design and build high-quality, scalable full stack applications using Next.js and TypeScript Develop and maintain cloud-native solutions on AWS, following well-architected and security best practices Design, build, and consume RESTful APIs, ensuring performance, reliability, and security standards are met Write ...

Full Stack Software Engineer

Hiring Organisation
Brio Digital
Location
London, Baker Street, United Kingdom
Employment Type
Contract
Contract Rate
£450/day
looking for two experienced Senior Full Stack Software Engineers to join a high-performing engineering team. You will play a senior role in the design and delivery of modern, scalable web applications, bringing strong full stack expertise across Next.js, TypeScript, and AWS in a programme delivering meaningful impact across … services nationwide. KEY RESPONSIBILITIES Design and build high-quality, scalable full stack applications using Next.js and TypeScript Develop and maintain cloud-native solutions on AWS, following well-architected and security best practices Design, build, and consume RESTful APIs, ensuring performance, reliability, and security standards are met Write ...

Python Developer

Hiring Organisation
Prolo
Location
City of London, London, United Kingdom
PostgreSQL, complex data modelling AI/ML : OpenAI integration, semantic search, conversational agents, unstructured data analysis and extraction Infrastructure : AWS (Lambda, ECS/EKS, API Gateway, S3) DevOps : Terraform, GitHub Actions, Helm, Infrastructure-as-Code Data Science : Graph analytics, data pipelines, ETL workflows, Jupyter notebooks Experience 5+ years … understanding of async programming Experience with Poetry or similar Python dependency management tools Experience building RESTful APIs and micro-services Solid understanding of database design and optimisation (both SQL and NoSQL) Experience with graph databases (Neo4j preferred) or willingness to learn quickly Knowledge of API design principles ...

Full Stack Engineer

Hiring Organisation
SR2 | Socially Responsible Recruitment | Certified B Corporation™
Location
London Area, United Kingdom
build. The team is small, collaborative, and deliberately high calibre. Engineers are trusted to take ownership, contribute to product direction, and work closely with design and commercial teams to shape what gets built. What you will be doing Building end to end features across backend and frontend, from APIdesign through to UI Working closely with product and design to turn ideas into well thought through functionality Improving performance, usability, and reliability of a live product used by real customers Contributing to technical decisions as the platform evolves and scales Owning meaningful parts of the product rather ...

Senior 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 ...

Full Stack Software Engineer

Hiring Organisation
83zero Ltd
Location
City, London, United Kingdom
Employment Type
Permanent
Salary
GBP 100,000 - 130,000 Annual
roles, with a track record of building solutions end-to-end Experience deploying applications in cloud environments, preferably Microsoft Azure Strong experience in REST API design and OpenAPI standards Extensive experience working with databases, data platforms, and analytical tools Ability to research, propose, and implement solutions with minimal ...

Full Stack Software Engineer

Hiring Organisation
83zero Ltd
Location
London, Lime Street, United Kingdom
Employment Type
Permanent
Salary
£100000 - £130000/annum
roles, with a track record of building solutions end-to-end Experience deploying applications in cloud environments, preferably Microsoft Azure Strong experience in REST API design and OpenAPI standards Extensive experience working with databases, data platforms, and analytical tools Ability to research, propose, and implement solutions with minimal ...

Senior Software Engineer

Hiring Organisation
TRITANIUM
Location
London Area, United Kingdom
systems that are safer, smarter, and dramatically more environmentally responsible. Location: London or Porto The Role We’re seeking a Senior Software Engineer to design, build, and maintain backend containerised services that power our scalable edge‐compute platforms. You’ll work closely with a Software Team Lead and collaborate … leadership while remaining hands‐on with complex systems. What You’ll Do Build production‐grade software using .NET C#, Python , and modern backend technologies Design and prototype services using containerised microservices Apply and challenge engineering best practices to continuously improve quality Make sound technical decisions in high‐impact areas ...

Back End Developer

Hiring Organisation
NearTech Search
Location
London Area, 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 ...

Lead Engineer, Risk Technology

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
clean, maintainable, performant applications; promote best practices, and collaborate closely with our quantitative and product teams. What You’ll Do High-Performance JVM Engineering: Design and build high-quality, scalable and performant low/zero-GC JVM services and APIs Technical Translation & Risk Modeling: Understand risk models & decompose complex … experience in architecting highly performant, low-latency systems. Testing Methodologies: In-depth knowledge of testing methodologies, including TDD, back testing and stress testing Software Design Excellence: Well versed in Agile methodologies, DRY, Clean Code, API design and micro-services. Technical Ecosystem: Experience in a full range ...

Full Stack Engineer

Hiring Organisation
Hotspex
Location
London, England, United Kingdom
enterprise-grade emotional brand science into the hands of every marketer → MCP server integrations and agentic tool chains — exposing our Human Motivation Framework as API-accessible AI tools that plug into Claude, Adobe, and enterprise martech stacks → Client-facing interactive products — brand simulators, revenue growth models, and AI-powered … Qualifications Proficient in front-end development: HTML, CSS, and modern JavaScript frameworks (React preferred) Skilled in back-end development: server-side languages, database management, API design Proven full-stack delivery — end-to-end ownership from architecture to deployment Strong experience with Claude Code — show us what ...

Full Stack Developer / Software Engineer

Hiring Organisation
Pro Contract Jobs Ltd
Location
West London, London, United Kingdom
Employment Type
Permanent, Work From Home
Salary
£80,000
Vue.js preferred; React/Angular also acceptable). Working knowledge of Python, plus exposure to Node.js and TypeScript in production settings. Strong understanding of API design and integration, and modern web development practices, tooling and patterns. Product-focused mindset with good commercial awareness and a bias toward delivering ...

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 ...

Contract Senior Software Engineer (Java or Python)

Hiring Organisation
SoCode Recruitment
Location
City of London, London, United Kingdom
generated code for correctness, security, and financial accuracy Desirable, but no essential: Experience with Apache Airflow or similar workflow schedulers REST or GraphQL API design experience Knowledge of fixed income, FX, or derivatives products and associated P&L/risk methodologies ...

Contract Senior Software Engineer (Java or Python)

Hiring Organisation
SoCode Limited
Location
London, Baker Street, United Kingdom
Employment Type
Contract
Contract Rate
£650 - £700/day
generated code for correctness, security, and financial accuracy Desirable, but no essential: Experience with Apache Airflow or similar workflow schedulers REST or GraphQL API design experience Knowledge of fixed income, FX, or derivatives products and associated P&L/risk methodologies ...

Senior Python Engineer: AI Agents & Forecasting

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
LangChain or LangGraph (agent memory, tool calling, state management) Dagster in production (assets, sensors, partitions) or equivalent pipeline orchestration Strong backend fundamentals including API design, async programming, and database modelling You've built systems that had to work reliably at scale, not just pass a demo Experience 5+ ...

Senior Data Engineer

Hiring Organisation
Haystack
Location
City of London, London, United Kingdom
cloud platforms is beneficial but not essential) Strong collaboration and communication skills 4+ years of experience in data-focused software development, including data modelling, design patterns, and building scalable, secure systems Working knowledge of software engineering principles and best practices, including testing, packaging, API design, DevOps, DataOps ...

Senior Full-Stack Engineer

Hiring Organisation
Addition
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£85,000 - £100,000 per annum
high standards for security, auditability, and compliance Main Skills Needed: Strong background in building and running production-grade systems Solid backend engineering expertise and API design experience Good understanding of relational databases and data modelling Experience working in regulated or audit-heavy environments Full stack capability across frontend ...

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

Hiring Organisation
Transreport
Location
City of London, London, 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 ...

Principal Solutions Architect

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
working hours, patterns and locations to suit you and our business. About the Opportunity As a Principal Solutions Architect, you will specialise in the design, development and governance of integrated digital project controls environments across major capital programmes. This is not a general IT solutions architecture role. … needed. Key Responsibilities Define enterprise aligned solution architectures for programme controls platforms covering cost, schedule, risk, performance reporting and data governance. Lead evaluation, selection, design and configuration of programme controls systems such as EcoSys, Oracle Primavera P6 and Unifier, Aconex, CDEs including SharePoint and ProjectWise, and related digital delivery ...