26 to 50 of 189 API Design Jobs in London

Senior Software Engineer, Inference Platform

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
after you’re helping with UI/UX, customer success, documentation and product ops. What You’ll Do Inference Platform Architecture & Core Services Design and build the company's inference service platform the backbone for serving AI models at scale across diverse workloads Own and architect core platform components … Gateway, Resource Orchestrator, Runtime Engines, and Autoscaler Design highly modular, scalable, and extensible low‐level designs (LLDs) for inference infrastructure components Lead high‐level design discussions, establish architectural patterns, and drive technical decision‐making for the inference stack Model Deployment & Lifecycle Management Understand and optimize the dynamics ...

Senior Java Developer

Hiring Organisation
CODEVERSE LIMITED
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£300 - £400 per day
experienced Senior Java/Python Engineer to join a high-performing Agile engineering team delivering secure, highly available and scalable microservices and API platforms. You will be hands-on with modern engineering technologies, working across microservices, APIs, Kafka, cloud databases, containers and observability, while also providing technical leadership … mentoring junior engineers. Key Responsibilities Design and develop scalable Java/Python microservices and REST APIs. Build and operate event-driven solutions using Apache Kafka . Design and optimise AWS Aurora PostgreSQL databases and data platforms. Deploy and support applications using Docker and Kubernetes . Develop API ...

Senior Java Engineer (AWS, REST, SOAP) – Hybrid – Sussex

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
engineering discipline, independent problem‐solving ability, and a commitment to building robust, scalable systems. You will work across modern cloud‐native architectures, contribute to API and microservices development, and help drive best practices across the engineering organisation. Key Responsibilities Design, develop, and maintain high‐quality Java applications using … Spring Boot. Build and optimise RESTful APIs and contribute to GraphQL service development. Develop cloud‐native solutions using AWS services such as Lambda, API Gateway, DynamoDB, ECS, S3, and others. Contribute to microservices architecture, event‐driven systems, and distributed design patterns. Implement CI/CD pipelines using tools ...

Senior Manager- Software Engineering

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Solution Architect

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Solution Architect - PERM OPPORTUNITY - SC REQUIRED

Hiring Organisation
Solirius Limited
Location
London, United Kingdom
Employment Type
Permanent
Salary
GBP 85,000 - 95,000 Annual
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 ...

Senior Software Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
Defence delivery team. This is a versatile, high-impact role designed for funded client delivery: you will build mission-critical web applications and API backends for central MoD programmes, while contributing to low-level system integrations (Kotlin, Android ART, IPC/AIDL) on tactical edge and Situational Awareness … platforms. You will sit at the intersection of modern enterprise software engineering and tactical edge integration, ensuring all code meets MoD Secure by Design (SbD) principles and Def Stan 00-056 safety boundaries. Full-Stack Application Development: Design and build resilient, secure web applications, microservices, and APIs (TypeScript ...

Senior Software Engineer | API Enterprise | Full-Stack

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
NVIDIA DGX SuperPODs to delivering real-time Language AI to over 300 million users and 200,000+ businesses globally. You will join the API Enterprise team. We sit at the intersection of DeepL's API platform and our Enterprise ecosystem. Whereas the Core team obsesses over the self … that enterprise IT and security teams depend on. We work hand-in-hand with a wide set of stakeholder teams to make DeepL's API the obvious and safe choice for global enterprises. We are shifting gears. We are moving from \"Software-First\" to \"Product-First\". ...

Fullstack Engineer (Backend)

Hiring Organisation
Randstad Technologies Recruitment
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
£450 - £550/day
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 ...

Python Application Developer with DevOps

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Python Application Developer with DevOps

Hiring Organisation
Jobleads-UK
Location
City Of London, England, United Kingdom
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 ...

Senior Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Lead Full Stack Developer London, United Kingdom MVNx Value Stream Engineering Company Priority[...]

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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. ...

Staff .Net Backend Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Engineer - Payments

Hiring Organisation
Appcast
Location
London, UK
Contribute to the 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 … Experience with Micro 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 ...

Principal Software Engineer (Back-End)

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Engineer - PayE

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Backend Engineer - UK

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Fullstack Developer — Java or Kotlin, React and TypeScript

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Fullstack Developer — Java or Kotlin, React and TypeScript

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Technical Lead - Java

Hiring Organisation
Sanderson Recruitment
Location
London, United Kingdom
Employment Type
Permanent
Salary
£95,000
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 ...

Principal Technology Architect - LLMs, agentic coding systems, intelligent IDEs, AI

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Software Engineer – Payment Capabilities

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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 ...

Senior Software Engineer, CalcGraphs - Vice President

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
fill the role of ‘Applications Development Technology Lead Analyst’ on the XiNG large scale distributed calculation platform (XiP). In this role you will design, build, and maintain the calculation engine at the heart of the XiP platform. This engine is responsible for c. 0.5 billion risk & suitability calculations … designing improvements to the distribution mechanisms of the engine which regularly parallelizes 250,000 hours of compute into a single 90‐minute execution: Lead design, development, and implementation of enhancements, focusing on optimizing distribution mechanisms, analyze current parallelization strategies, and identify opportunities to further improve efficiency, scalability, and throughput. ...

Blockchain Software Developer - Digital Assets Platform

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
role for a developer who is deeply enthusiastic about the intersection of decentralized technologies and institutional finance. The successful candidate will contribute to the design, development, and deployment of Web3-native components and integrations that power Citi's digital asset infrastructure — spanning tokenization, smart contracts, on-chain settlement … Web3 engineering fundamentals, a curiosity for emerging blockchain ecosystems, and the ability to bridge decentralized technology patterns with enterprise-grade software standards. Key Responsibilities Design, develop, and deploy Web3 components and integrations for Citi's Digital Asset Platform, including smart contracts, on-chain event listeners, wallet integrations, and blockchain ...