26 to 50 of 60 API Design Jobs in London

Staring at a hard problem with no playbook and real consequences. We do not care about the title. We care about whether you can design a backend system from first principles, defend every trade-off under pressure, and own the outcome when the requirements change at 11pm … about reached them with the right story at the right moment, they would listen. What you will own → The backend architecture . You will design the core services powering Healf's Wellbeing Intelligence platform from first principles. The API layer, the data pipelines, the async processing, the infrastructure ...

into a repeatable process. What you'll do Phase 1 (0-3 months): Lead the greenfield implementation of all core platforms. Build foundational REST API integrations and webhook-driven automations. Define the cross-platform data model - canonical field mapping, entity relationships and data quality standards across … automations in JavaScript and Python - ticket routing, billing triggers, licence lifecycle, CRM sequences, alert-to-action logic. Build and maintain Azure middleware (Logic Apps, API Management, Service Bus) as IaC via Terraform through a CI/CD pipeline. Iterate the acquisition onboarding playbook. What we're looking for * 5+ ...

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 ...

building and knowledge-sharing initiatives Skills & Experience Required Significant senior backend development experience with strong Python proficiency (async programming, concurrency, multithreading) Expertise in RESTful API design, OpenAPI/Swagger documentation and API lifecycle best practices Hands-on experience with ML libraries: PyTorch, PySpark, scikit-learn, Hugging Face … machine learning, cloud computing or data engineering highly advantageous Professional accounting qualification desirable but not required Nice to Have Experience with Microsoft Graph API Background in audit, financial services or regulated industry technology What's on Offer A competitive salary and benefits package, flexible hybrid working across 20+ ...

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 ...

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 ...

contribute to architectural decisions, champion engineering best practices, and help shape how the team builds and scales as the business grows. Key Responsibilities: Design, build, and maintain scalable, resilient backend services and APIs in Go Collaborate closely with product, engineering, and operations to deliver high-quality, well-tested software … consider engineers whose background is in Python provided they have practical Go experience Solid understanding of microservices architecture and REST and/or gRPC API design Comfortable working with AWS and Docker-based environments Experience with relational and/or NoSQL databases and event-driven systems Collaborative ...

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 ...

working on the underlying systems that make complex visualisations fast, accurate, and scalable. The challenges range from rendering performance and interaction design through to algorithms, graphics, API design, and numerical correctness. What you’ll be doing Designing and building core charting features used by developers around … exceptionally high technical standards High levels of ownership and autonomy Small team, significant impact Opportunity to deepen expertise in performance, graphics, visualisation, and systems design Package Salary up to £200,000 Hybrid working (London) Private healthcare Pension Additional benefits If you’re interested in building the technology behind modern ...

hybrid role , with three days per week in a Central London office and two days remote. What You'll Do: Build Core Platform Services Design and develop the APIs, services, and data models that power customer consultations, prescriptions, subscriptions, and order generation. Own Features End-to-End Take backend … solid commercial experience building production backend services and APIs using Python, and can confidently discuss complex projects you've delivered You understand data modelling, API design, testing practices, and how to build maintainable software at scale You build defensively and care about correctness, recognising the real-world impact ...

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 ...

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 ...

products (e.g., Concierge an agentic AI workflow tool, Prism a Mercer knowledge fabric for scheme data, and similar initiatives), from problem framing and design through build, release, and support. Translate risk advisory/consulting needs into clear technical requirements, user stories, and solution designs; partner with stakeholders through … Proven experience as a Tech Lead/Lead Engineer delivering production software, including hands-on coding and code review ownership. Strong backend engineering skills (API design, data modelling, performance) and experience building secure, role-based applications. Experience working directly with business stakeholders in a financial firm, with ...

role, with strong backend expertise in Typescript and Node and front capability in React Proficiency in SQL, Redux, cloud services (AWS or GCP), RESTful API design and GraphQL Strong analytical skills with the ability to design, optimise, and troubleshoot complex UIs Excellent communication and leadership skills; ability ...

assisted development workflows. ● Agile Experience: Proven track record working within Agile teams and participating in iterative delivery. ● Core Engineering: Proficiency in Git, REST API design, and modern CI/CD practices This is a great opportunity to work for an exciting organisation and to start ASAP. The role ...

founding team Build technology that fundamentally changes how teams use data What We Are Looking For Strong experience building in Python Deep understanding of design patterns and system architecture Experience building scalable, performant platforms Strong grasp of event-driven systems and concurrency Solid database and API design … Have Zero-to-one product experience, including OSS or side projects Data engineering experience such as pipelines and analytics Experience integrating LLMs, including prompt design and understanding model capabilities Deeper cloud experience, especially with GCP Experience with Encore, though this is easy to pick up Ways of Working Ownership ...

improving APIs that support critical platform functionality Investigating production issues and tracing problems across distributed systems Working with product and engineering teams to design scalable solutions Improving reliability, observability and performance across existing services Reviewing code, sharing knowledge and helping raise engineering standards across the team Tackling real-world … APIs used by customers or internal teams Other Skills Needed: Solid backend engineering experience in C#, Java, or Go, with a strong grasp of API design and architecture. Hands-on experience managing and debugging production systems across cloud and self-managed infrastructure. Proven ability to navigate complex third ...

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 ...

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 ...

Senior Software Engineer — AI & Multimodal Data Platforms About the Role We are seeking an experienced Senior Software Engineer to help design and build next-generation AI systems used in Defence, Security, and Resilience environments. You will work on a cutting-edge multimodal data fusion platform that transforms large-scale … closely with senior technical leadership, platform engineers, security stakeholders, and mission-focused teams to deliver robust, scalable, production-grade software. What You’ll Do Design, build, and operate core platform components across the AI and data stack. Develop distributed systems that ingest, transform, and serve diverse multimodal datasets. Contribute ...

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 ...

Knowledge Graph Architect 6 months Remote/London £Negotiable - INSIDE IR35 KEY SKILLS Neo4j schema design Ontology engineering Graph RAG API design Disclaimer: This vacancy is being advertised by either Advanced Resource Managers Limited, Advanced Resource Managers IT Limited or Advanced Resource Managers Engineering Limited ("ARM"). ...

stuck into some genuinely interesting engineering. Think computational complexity, mathematical optimisation, and performance challenges at scale - a long way from your average API job. Requirements: 7+ years experience developing and maintain scalable Python/FastAPI back-end services Ideally worked with high-performance APIs for complex hierarchical data queries … code Lead technical planning by breaking down roadmap items into scoped engineering work, driving ADRs and setting standards for code quality, testing, and API design Collaborate cross-functionally with front-end, data engineering, modelling and product teams to deliver reliable, impactful features Line-manage a team ...

platform ⌈Azure, Databricks⌋, but this role is heavily focused on the software engineering and integration side of things. The journey starts by owning complex API layers and mentor growing engineers, whilst yourself growing into the responsibilities of a Head of Engineering. I learnt something new today → The events world … relies entirely on third-party connectivity, and you'll own the API layers to enable to Azure Data Platform. WHY THIS ROLE You get to stay close to the tech, leading code reviews and driving software standards. True mentorship focus—they have bright junior devs ready to learn from ...

scalable APIs and integration solutions. Key experience required: Active and transferable SC Clearance Sole British National Hands-on MuleSoft development experience MuleSoft Anypoint Platform API design and development Mule flows, connectors and runtime environments Salesforce integration experience Java, REST/SOAP APIs, JSON and XML Security and encryption … knowledge including OAuth2, JWT and API gateways CI/CD and version control experience Salesforce Platform Developer or MuleSoft certification would be beneficial. Immediate start available, subject to checks. ...