1 to 25 of 52 API Design Jobs in London

London office About The Client: Our client is a rapidly growing Infrastructure-as-a-Service (IaaS) provider driving digital transformation. Key Responsibilities: Architecture & System Design Design and evolve scalable backend services and product components. Make sound architectural decisions across APIs, services, and data layers. Lead delivery from design … high coding standards and test coverage. Contribute to code reviews and documentation. Mentor engineers and support technical growth. Collaboration Work closely with Product and Design to deliver scalable solutions. Communicate technical trade-offs and manage cross-team dependencies. Essential skills and requirements: Strong experience building production backend systems ...

confidence. You’ll play a key role in bridging backend data with frontend interfaces while helping shape new initiatives across the product landscape. Responsibilities Design and develop APIs that standardise access to complex internal datasets (ideally using NestJS, TypeScript, Kong) Apply thoughtful design practices including API versioning … Qualifications Strong experience with modern JavaScript and TypeScript on both backend (Node.js/NestJS) and frontend (React/Redux) Required Skills Solid understanding of API design principles (auth, scalability, security) Ability to work with diverse data formats such as CSVs, JSON, lists, etc. Experience writing complex database queries ...

Build agents that can verify the quality of the code and identify error patterns. Hypothesize on steps in the software engineering cycle (prototyping, architecture design, API design, production implementation, launch, experiments, monitoring, operational maintenance) and evaluate model capabilities on them Design verification mechanisms that can automatically … experience. Strong expertise in building full-stack applications and deploying scalable, production-grade software using modern languages and tools. Deep understanding of software architecture, design, development, debugging, and code quality/review assessment. Excellent oral and written communication skills for clear, structured evaluation rationales. Engagement Details: Commitment : flexible engagement ...

Build agents that can verify the quality of the code and identify error patterns. Hypothesize on steps in the software engineering cycle (prototyping, architecture design, API design, production implementation, launch, experiments, monitoring, operational maintenance) and evaluate model capabilities on them Design verification mechanisms that can automatically … experience. Strong expertise in building full-stack applications and deploying scalable, production-grade software using modern languages and tools. Deep understanding of software architecture, design, development, debugging, and code quality/review assessment. Excellent oral and written communication skills for clear, structured evaluation rationales. Engagement Details: Commitment : flexible engagement ...

scale - component lifecycle, rendering behaviour, and bundle architecture are instincts - TypeScript mastery in strict mode - complex generics, discriminated unions, conditional types, and type-safe API boundary design - Vite and modern build tooling; tree-shaking, chunk strategy, module federation, and build performance optimisation in CI - State management at scale … composite lifecycle, memory profiling, GC pressure, and long-task detection - WebGL, Canvas, or custom rendering engine for high-density, real-time financial data visualisation - Design system ownership - token architecture, component API design, versioning strategy, and cross-team adoption at scale - Testing discipline: unit, integration, E2E (Playwright/ ...

scale - component lifecycle, rendering behaviour, and bundle architecture are instincts TypeScript mastery in strict mode - complex generics, discriminated unions, conditional types, and type-safe API boundary design Vite and modern build tooling; tree-shaking, chunk strategy, module federation, and build performance optimisation in CI State management at scale … composite lifecycle, memory profiling, GC pressure, and long-task detection WebGL, Canvas, or custom rendering engine for high-density, real-time financial data visualisation Design system ownership - token architecture, component API design, versioning strategy, and cross-team adoption at scale Testing discipline: unit, integration, E2E (Playwright/ ...

Role We’re hiring a Backend Engineer to build the core infrastructure behind Revax’s AI-native platform for professional services. You’ll design, optimise, and scale the systems that power multi-agent drafting, knowledge graphs, and auditable AI workflows used by accountants, tax advisors, and consultants at leading … graphs, and real-world enterprise workflows. What You’ll Do Build & own core backend systems · Build and optimise databases for complex, real-world data · Design and implement APIs using FastAPI for AI workflows and product features · Build and scale LangGraph-based multi-agent systems with checkpointing, retries, and observability ...

developer to support the development and deployment of the AWS Professional Supply Chain Command Centre solution. This role will focus on backend service development, API design, event tracking, and analytics integration across supply chain flows involving suppliers, manufacturing, and distributors. Location: London, UK (Hybrid) Contract role … experience in AWS backend development (Node.js, Lambda, ECS, Step Functions). Strong understanding of supply chain processes and event-driven architectures. Experience with API design, CI/CD pipelines, and AWS services like Neptune, RDS, DynamoDB, and S3 Familiarity with analytics tools and KPI frameworks for supply chain ...

venture backed by the strength and stability of an established business. Key Responsibilities End-to-end development of high-quality, scalable SaaS platforms from design through deployment and maintenance. Architect and implement robust backend services primarily using Python and PostgreSQL. Develop and maintain responsive, performant front-end applications with … Provide technical mentorship and leadership to development teams, fostering best practices in coding, testing, and deployment. Participate in code reviews, architecture discussions, and system design decisions. Troubleshoot and resolve complex technical issues across the full stack. Ensure software security, scalability, and performance are maintained at all times. Keep abreast ...

Tailwind CSS to deliver end-to-end features. Data Architecture: Deep experience with diverse data stores, specifically PostgreSQL , ElasticSearch , and NoSQL (MongoDB), including schema design and performance tuning. System Design: Expert knowledge of RESTful API design and complex asynchronous request handling . Technical Leadership: Experience ...

will be a hands-on technical leader who defines direction, raises engineering standards, and delivers measurable product outcomes, all while remaining deeply involved in design and development. This is not a traditional people-management or delivery-management role—here, you will write code, architect solutions, lead complex projects … role is perfect for leaders seeking high-growth, product-driven environments, who are passionate about distributed systems, and who want to directly influence the design of secure, scalable, and resilient infrastructure while cultivating top engineering talent. What You'll Do: Architect and design scalable, resilient, high-performance backend ...

GraphQL specialist ready to lead the integration layer of a major HR systems programme? Our client is seeking a Hasura DDN Integration Engineer to design and deliver a centralised integration platform connecting a core HR system with several external services. The project requires expertise in Hasura, GraphQL, and microservices … This is a hands-on contract role, ideally suited to a senior integration engineer with strong experience in Hasura DDN (or Hasura v2), GraphQL API design, and complex system integrations . The Role Working within a multi-vendor delivery environment, the successful candidate will take ownership ...

Senior Developer, Back End, API, .Net SQL, NW London to £80K (office based role) A Senior Back End Developer is required to join this established financial software house based in North London. They work with some of the leading brands in retail and media, offering financial management systems developed … required with expertise in .NET, C#/VB, SQL Server, and SAP Business One integration. The ideal candidate should have strong skills in RESTful API development, database optimization, and Azure DevOps pipeline management. Knowledge of API security, CI/CD automation, and Swagger documentation is recommended. Responsibilities API ...

consulting company focused on building innovative solutions that address clients’ most complex digital transformation needs. Leveraging our holistic portfolio of capabilities in consulting, design, engineering, and operations, we help clients realize their boldest ambitions and build future-ready, sustainable businesses. With over 230,000 employees and business partners across … ever-changing world. Role Summary We are seeking an AI Architect with deep hands-on experience in AI/ML and Generative AI to design and govern end‐to‐end solutions across application, data, and infrastructure layers. The Architect will own reference architectures , lead solution shaping , and ensure responsible ...

agile squad, responsible for the end-to-end delivery of scalable web applications. What You’ll Do (Responsibilities) End-to-End Development: Design and develop high-volume, low-latency applications for mission-critical systems. Back-End Excellence: Write clean, maintainable code using Java and the Spring Boot ecosystem. Front … Innovation: Build responsive, user-friendly UI components using React, Angular, or Vue.js . Database Management: Design and optimize schemas for relational ( PostgreSQL/MySQL ) and NoSQL databases. API Design: Build and consume secure RESTful APIs to integrate with internal and third-party services. Collaboration: Participate in code ...

will coordinate with the rest of the team working on different layers of the infrastructure. Therefore, a commitment to collaborative problem solving, sophisticated design, and quality product is important. Responsibilities Working in a team of Front-End engineers Writing clear & concise code Working closely with Back-End engineers Participate … architecture design code reviews API design with the Back-End engineers and other team members to establish more functional, cohesive code Create, maintain documentation while implementing the best coding practices standards Hands-on approach Participation in sprint rituals What you’ll need 6+ years experience developing large ...

that integrate development finance datasets (e.g. OECD, IATI, World Bank, IMF, WHO, etc.) into a unified knowledge graph. Scaling the Knowledge Graph, including schema design, data integration, and optimisations. Developing the data quality framework, implementing provenance tracking, quality indicators, coverage metrics, and automated testing so that every data point … Spanner through the Data Commons infrastructure, alongside BigQuery for internal analytical workloads and MySQL for supporting services. Key responsibilities: Data infrastructure and pipelines Design, build, and maintain open-source ETL/ELT pipelines that ingest, clean, transform, and deliver development finance data from multiple sources. Contribute to data modelling ...

APIs, managing infrastructure with Cloudformation, and building modern user interfaces with React. You will work on a high-traffic system that handles billions of API calls, requiring strong attention to scalability, performance, and reliability. Key Responsibilities Design, develop, and maintain microservices and RESTful APIs (Node.js + AWS Lambda … Handle data and queries using relational databases (e.g., PostgreSQL) Collaborate in designing and developing the user interface using React Integrate and monitor AWS services (API Gateway, S3, CloudWatch, RDS, CloudFront, etc.) Ensure testability, code quality, and DevOps best practices Technical Requirements Minimum of 5 years of experience in full ...

seeking a Senior Java Developer to join a modern engineering team building high-performance, cloud-native services. You will take ownership of backend design and delivery, mentor engineers, and help elevate engineering standards. A key focus of this role is accelerating team capability with GitHub Copilot —we are looking … genuine enthusiast who uses it daily, understands the newest features, and can coach others to use it safely and effectively. Key Responsibilities Design, build, and optimise microservices and APIs using Java 21 . Drive best practice in code quality, testing, secure coding, and performance tuning. Build and integrate with ...

core stack includes: The Engine: Expert-level C# and .NET Core mastery. Architecture: Deep understanding of SOA (Service Oriented Architecture) and complex Object-Oriented design patterns. System Dynamics: Specialized knowledge of concurrency, asynchrony, and parallelism —essential for real-time transactional processing. Data & Web: High proficiency in SQL Server … API design, and modern front-end fundamentals (HTML/CSS/JS). Reliability: A strict practitioner of TDD (Test Driven Development) and robust CI/CD processes. Desired Innovations Our client is actively modernizing. Exposure to the following is highly valued: Cloud & Orchestration: Azure ecosystems, Docker ...

Onsera's core product platforms, from wearables integration and health data pipelines to member payments and AI workflows. As a player-coach, you'll design and implement full-stack solutions while setting engineering standards and help build and mentor our engineering team as we scale. This role offers … opportunity to shape API-first architectures, lead complex integrations with healthcare partners and SaaS platforms, and transition into engineering leadership as the organization scales. What You'll Do Own technical delivery of multiple Onsera products from design through production and iteration Design and implement full-stack solutions ...

pure DevOps role. You will spend significant time on platform engineering, CI/CD, and infrastructure – but you will also contribute to application development, API design, and integration work. We need a generalist who leans platform, not an infrastructure specialist who only touches pipelines. What … fast diagnosis and recovery. • Define and track availability and reliability targets; drive post-incident review and preventative improvements. Application Development • Contribute to backend development: API endpoints, service logic, database schema, and integration code. This is a building role, not only an operations role. • Design and implement integration patterns ...

people actually love to use? We are representing a globally recognized digital product studio that sits at the sweet spot of high-end aesthetic design and hardcore engineering. They're looking for a Senior & Lead Full-stack Engineer to join the growing function. This isn't a "ticket-taking … robust, scalable backend. What You Bring to the Table React Node/TypeScript/JavaScript Cloud: AWS, Azure, or GCP. APIs: API design and integration (REST & GraphQL). Databases: SQL, NoSQL, real-time, etc. AI Tooling: Confident using AI-boosted environments to ensure quality (Claude or similar). ...

Security Architecture Deep knowledge of IAM, encryption, compliance frameworks Ability to enforce security controls across cloud environments Integration Architecture Knowledge of event‐driven patterns, API design, and hybrid connectivity Non‐Functional Requirements Expert in designing highly available, fault‐tolerant and resilient systems Experience with observability, monitoring, disaster recovery ...

development tools across your team Foster culture of learning, experimentation, and knowledge sharing Work with Head of Engineering on architecture, partner with product and design teams About You You're a strong senior engineer ready to lead a team but who still loves writing code. You have solid technical … Strong expertise in Python backend development with async patterns Production experience with modern frontend frameworks (React, TypeScript) Solid understanding of distributed systems architecture and API design Experience with container orchestration, CI/CD, and cloud platforms Experience with NoSQL databases and data modelling Daily user of AI-assisted ...