26 to 50 of 171 API Design Jobs in London

technology stack, from backend services and distributed data architecture through to responsive user interfaces, production support, and engineering best practice. Key Responsibilities Lead the design, development, and delivery of backend services and platform components using Java 8+/Spring Boot and Python/FastAPI. Build, enhance, and operate event … driven, real‐time data pipelines using Kafka and related streaming technologies. Provide deep technical expertise in distributed systems, data architecture, and scalable platform design. Design, implement, and maintain Java‐based APIs and microservices, including REST, OpenAPI, GraphQL, and gRPC services. Work with modern data technologies including PostgreSQL, MongoDB ...

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 ...

Opportunity You will join a high-impact development squad building commercial offerings on top of the thriving open-source Backstage framework. You will design and build backend systems, APIs, and developer portals that elevate the developer experience across external commercial clients and internal engineering teams alike. Your Impact Backend … API Systems: Design, build, and maintain scalable backend services and APIs primarily using TypeScript, Node.js, and modern web technologies. Developer Experience & Infrastructure: Build and operate infrastructure, developer toolsets, and CI/CD deployment pipelines to streamline engineering workflows. Engineering Excellence: Elevate code quality through technical RFCs, code reviews ...

Solirius Reply, part of the Reply Group, is a technology consultancy and digital transformation partner that helps organisations solve complex challenges through strategy, design, engineering, and delivery. We work closely with our clients to deliver secure, accessible, user-focused services that evolve with their needs. By combining deep technical … expertise with people-centred design, we create solutions that deliver meaningful, lasting impact. Our consultants partner directly with client teams, embedding into organisations to understand their goals, challenges, and users. This collaborative approach enables us to deliver tailored solutions that drive measurable outcomes across public and private sectors. Past ...

play a key part in driving the adoption of AI across engineering, leveraging emerging technologies and embedding AI-native workflows to improve how we design, build, and deliver software. This role is predominantly hands‐on, with around 20–30% of time on technical leadership: architecture, mentoring, and shaping … generated code to our standards for security, reliability, and cost-efficiency (FinOps). These are first-class concerns in agentic pipelines, not afterthoughts. Design, build, and operate software across our platform, applying the same rigor to AI-augmented work as to anything else you ship. Embed deeply with Product ...

environment Qualifications Hands-on experience in production environments as a Software Developer and DevOps/Platform Engineer Strong production experience with Python and software design patterns (SOLID, DRY) Expertise in AWS (or similar cloud providers), Containerization and Kubernetes Deep understanding of RESTful API or GraphQL API design ...

team? Hands-on experience in production environments as a Software Developer and DevOps/Platform Engineer Strong production experience with Python and software design patterns (SOLID, DRY) Expertise in AWS (or similar cloud providers), Containerization and Kubernetes Deep understanding of RESTful API or GraphQL API design ...

Python (pyspark): Experience with data pipelines and analytics is a plus. Power BI: Familiarity with developing dashboards and data models. Architecture: Knowledge of microservices, API design, and event-driven architectures. DevOps/CI/CD: Experience with Azure DevOps, GitLab, GitHub Actions, or similar tools. Cloud Platforms: Proficient … Azure or AWS (Azure preferred). Databases: Strong skills in SQL Server, PostgreSQL, or other relational databases. Key Responsibilities Design & Develop: Create and maintain full stack applications using React JS and C#.NET Core. Build Services: Develop high-performance backend services and RESTful APIs with a focus on scalability ...

solutions and enabling tangible value through technology. This role is a full-stack engineering role (covering frontend, backend, data, infrastructure) and collaborates on solution design, implementation, deployment, testing and support.**Responsibilities:*** Design, build, and improve modern application services that support a strategic business platform, with a focus … strong track record of delivering production systems.* Strong experience building backend applications and APIs, ideally in Java* Practical experience across service-based architecture, API design, integration patterns, and modern web application delivery.* Experience contributing to modernisation or platform evolution initiatives is strongly desirable.* Strong engineering discipline across testing ...

digital platform, shaping APIs, integrations and user‐facing components that directly enable new propositions and end‐to‐end customer journeys.## **What you will do*** Design, build and maintain cloud‐native backend and frontend components, including APIs, microservices, integrations and digital interfaces.* Deliver end‐to‐end digital capabilities with … Technical Leads and Architects to refine requirements and translate them into robust technical solutions.* Apply modern engineering practices such as AI-SDLC, event‐driven design, microservices architecture, containerisation and infrastructure‐as‐code.* Support CI/CD pipelines, automated testing, observability and operational readiness to enable reliable and frequent deployments. ...

first‐class concerns. Inputting into architecture and technical direction in collaboration with Principal Engineers – making considered, well‐reasoned decisions on service boundaries, data design, messaging patterns, consistency guarantees and performance. Championing a high‐quality engineering culture – test coverage, peer review, CI/CD discipline via GitHub Actions, Infrastructure … proven senior-to-staff-level backend engineer with deep, current expertise in C# and .NET Core 8/9 – you can architect and lead design of distributed REST API microservices at scale. Authority in AWS serverless architecture – Lambda‐first, with strong working knowledge of API Gateway ...

maintain high standards of engineering quality.**How you will make an impact*** Build and maintain reliable JVM-based services using Kotlin or modern Java.* Design and develop well-structured APIs and integrations.* Build reusable services, APIs and components that enable other teams to deliver consistently and reduce duplication.* Contribute … API design standards, documentation and versioning across services.* Deliver complete end-to-end features by connecting backend services and data models with responsive web interfaces.* Use appropriate test-first and test-informed practices to create effective automated tests.* Experiment with AI-assisted engineering tools where they provide clear ...

maintain high standards of engineering quality. How you will make an impact Build and maintain reliable JVM-based services using Kotlin or modern Java. Design and develop well-structured APIs and integrations. Build reusable services, APIs and components that enable other teams to deliver consistently and reduce duplication. Contribute … API design standards, documentation and versioning across services. Deliver complete end-to-end features by connecting backend services and data models with responsive web interfaces. Use appropriate test-first and test-informed practices to create effective automated tests. Experiment with AI-assisted engineering tools where they provide clear ...

work on the back-end team — leading planning, architecture, and code quality. You will work closely with the wider product and engineering team to design, develop, and maintain the back-end services that power our platform. This hybrid role is based out of our London office near Waterloo Station … reports to the Head of Platform. Responsibilities Back-end development & architecture Design, develop, and maintain scalable back-end services and APIs using Python and modern frameworks (FastAPI). Design and build high-performance API endpoints to handle complex hierarchical data queries and multi-dimensional aggregations for grid ...

development of our next-generation platform channels. Partner on the delivery of new products while continuously maintaining and improving existing ones. Architecture & Design: Collaborate with team members and engineering leaders to design new services and components utilizing our internal Request for Comments (RFC) process. End-to-End Ownership … Frontends (MFEs) is a major plus. DevOps & Cloud: Hands-on experience with Docker, Kubernetes, Terraform , and AWS . Foundations: Strong understanding of system architecture, API design, scalable service integration, Linux systems, and Git version control. Core Soft Skills: Strong knowledge of basic algorithms, object-oriented/functional design ...

startup with experience building SaaS products. You will also have a deep understanding of the key challenges engineers face and a firm grasp on design principles in prioritizing key features and capabilities. Your superpower is how to bridge the gap between technical specifics and business needs effortlessly and turn … engineering mastermind behind Heidi developing AI products which will change the face of healthcare Autonomously deliver beautiful & robust code with considerations on code structure design and scalability. Implement and optimize data storage solutions. Design, build, and maintain high-performance backend systems using Python. Architect and manage cloud infrastructure ...

systems that enable global commerce, while evolving an existing real-time platform to support new markets. You will address backend capacity constraints and help design a shared transaction and ledger layer used across multiple business lines. This is a hands-on senior engineering role requiring both high-quality delivery … strong technical leadership in ambiguous, high-scale environments. You will be expected to: Design scalable systems with correctness and failure modes considered from the outset Clarify and scope requirements before proposing solutions Make pragmatic trade-offs in system design, avoiding over-engineering Operate independently without reliance ...

deliver against them. It is not a programme, delivery or governance position: you make the architectural calls rather than facilitate them. You will: Design large-scale agentic AI architectures: LLM document processing, structured extraction, RAG, invoice-to-contract matching Own low-level design decisions, including API design ...

helping shape modern platforms that leverage Agentic AI, workflow orchestration, and intelligent automation to solve complex business challenges. What You'll Do Lead the design and delivery of scalable Java 17+/Spring Boot microservices Own architecture decisions, system design, and engineering standards Design resilient, high-performance … adoption of AI engineering tools including GitHub Copilot, Cursor, and Claude Code Deliver AI-powered features using LLMs, RAG, semantic search, and intelligent automation Design workflow orchestration solutions using Camunda or similar BPM platforms Lead the implementation of Agentic AI capabilities, autonomous workflows, and AI-driven decision making Drive ...

delivery methodology to ensure timely and high-quality delivery of software applications. Technical Ownership: Take technical ownership of a product or software solution, covering design, estimation, shaping, and user story/requirement creation. Solution Documentation: Document solutions, including architecture, configuration, release, and support handover. Stakeholder Collaboration: Collaborate and liaise … practices and modern architectural patterns, including microservices and message-driven architectures. Non-Functional Requirements: Experience developing applications with non-functional requirements in mind. Application Design: Experience in application/digital services design. Software Engineering Practices: Proficiency in software engineering practices like code reviews, CI/CD pipelines, and SOLID ...

Required Technology 15+ years of progressive software engineering; 5+ years leading AI‐native solutions at enterprise scale. Hands‐on with LLMs and agentic frameworks; design and deploy AI systems that augment SDLC (requirements → coding → testing → ops). Tooling & Platforms (practitioner proficiency) Claude Code (Anthropic) for secure, context‐rich code …/Gemini for research workflows where permitted; govern enterprise knowledge ingestion. Architecture & Integration Distributed systems, microservices, cloud‐native (Azure/AWS/GCP); secure API design (REST/GraphQL). MLOps & AIOps: CI/CD for AI, model lifecycle (eval, versioning, rollout/rollback), guardrails, telemetry, drift monitoring ...

Design, build, and evolve payment services and capabilities that enable seamless customer transactions across M&S digital platforms. Develop resilient backend services, APIs, and integrations that support millions of customer payment journeys every year. Own features end-to-end, taking responsibility for solution design, development, testing, deployment … testing, and maintainability. Proficient in driving operational excellence through observability and modern engineering practices. Highest-signal resume keywords Java Engineering Expertise Backend Service Development API Design and Integration CI/CD Implementation Observability and Monitoring Hard Skills Backend Development API Development System Design Scalable Systems Resilient ...

developer experience, providing tools and infrastructure that support agile methodologies and continuous integration/continuous deployment. Identify problems, propose solutions, and execute software design, development, operations, and technical troubleshooting. Develop secure, high-quality full stack production code, and review and debug code. Support the products you build through … team culture of diversity, opportunity, inclusion, and respect. Required Qualifications, Capabilities, and Skills Practical knowledge of the full software development lifecycle, including system design, application development, testing, and operational stability. Ability to develop, debug, and maintain code using modern programming languages and database querying languages. Good understanding of Java ...

where correctness, transparency and performance matter. You'll have real ownership, from architecture through deployment, across new and existing products. What You'll Do Design, build and ship features across the full stack (Fastify microservices, React/MUI, shared TypeScript packages in a pnpm monorepo) Design and evolve … backend services for high-volume, distributed screening workloads Build event-driven pipelines (AWS SNS/SQS) with idempotent consumers, DLQs and batch processing Design clean APIs and contribute to architecture across multiple products Integrate external identity, KYC and payments platforms (e.g. Senzing, Auth0, Stripe) Own services ...

Senior .Net Developer, C#/VB.Net, API, SQL, NW London to £85K A 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 in house … required with expertise in Visual Basic .NET, C#, 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 ...