1 to 25 of 48 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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

function, responsible for enabling Real Time data, event-driven architecture, and high-performance integrations across the organisation. * The ideal candidate will contribute to the design, development, and scaling of Intact's Confluent-based streaming platform, supporting teams across the organisation in adopting event-driven approaches. * This opportunity sits within … modernisation programme, leveraging Agile and DevOps practices to continuously deliver business value. Key Accountabilities * Deliver engineering tasks across the Confluent Streaming Platform, including the design, development, testing, and deployment of event-driven services and data pipelines. * Develop Kafka topics, schemas, and streaming applications using Kafka, Kafka Connect, Schema Registry ...

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 ...

function, responsible for enabling Real Time data, event-driven architecture, and high-performance integrations across the organisation. The ideal candidate will contribute to the design, development, and scaling of Intact's Confluent-based streaming platform, supporting teams across the organisation in adopting event-driven approaches. This opportunity sits within … modernisation programme, leveraging Agile and DevOps practices to continuously deliver business value. Key Accountabilities Deliver engineering tasks across the Confluent Streaming Platform, including the design, development, testing, and deployment of event-driven services and data pipelines. Develop Kafka topics, schemas, and streaming applications using Kafka, Kafka Connect, Schema Registry ...

momentum Technical skills required: Strong TypeScript across both frontend and backend (Node.js) Modern frontend framework experience (React or similar) RESTful and/or GraphQL API design and development Database design and querying (SQL and/or NoSQL) Experience in regulated or data-sensitive industries a strong advantage ...

fast-moving startup environment. The Role Technical Strategy & Leadership Work alongside the founder to define and evolve the technical roadmap Lead architectural design and critical technology decisions Champion engineering best practices, code quality, and technical excellence Mentor, coach, and grow engineers at all levels Foster a culture of ownership … collaboration, and innovation Backend Architecture & Development Architect, build, and scale backend services and RESTful APIs Design, optimise, and maintain MongoDB database solutions Improve system reliability, performance, and scalability Resolve complex production issues with robust solutions Implement microservices and modern backend patterns Collaboration & Delivery Partner with Product, Design ...

remaining close to complex technical problem-solving. Key Responsibilities Lead and develop a high-performing engineering team Own delivery outcomes, quality, and engineering standards Design and evolve distributed, event-driven systems Partner with architecture and senior engineering stakeholders Drive continuous improvement across tooling, CI/CD, and testing Communicate … experience leading engineering teams in an Agile environment Strong expertise in C# and modern .NET/.NET Core Experience building distributed, event-driven systems API design and development (REST, GraphQL) Relational databases (SQL Server, MySQL, or similar) Cloud platforms such as AWS or Azure Solid understanding ...

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 ...

backend engineer who enjoys designing systems properly and taking ownership of production infrastructure. You will likely bring experience with: • PostgreSQL/SQL database design, schema architecture, indexing, migrations • NoSQL databases such as Firestore • Database migrations from NoSQL to relational systems • REST API design for high concurrency • Stripe … product aiming to redefine how music is created online. You will: • Lead the migration from Firestore to PostgreSQL • Build the payments backbone powering subscriptions • Design scalable media upload and streaming systems • Build backend systems for real-time music collaboration • Improve reliability, observability, and deployment pipelines The team works from ...

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 ...

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 ...

Should be able to write unit test cases using any of the frameworks and should be completely automated. Should have strong exposure in REST API design principles. Should be able to develop reusable components using proper design patterns and implement the right solutions. Should be able ...