1 to 25 of 87 Permanent API Design Jobs in London

Domain Architect - Integration

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
modernisation approaches that support business agility, resilience, cost control and long-term maintainability. Platform and Technology Direction Provide architecture leadership for enterprise integration platforms, API management, messaging and eventing capabilities. Ensure platforms are scalable, secure, resilient, observable and fit for current and future needs. Support platform roadmap planning, lifecycle … programmes on integration options, service boundaries, non-functional requirements, dependencies and risks. Support solution options, high-level designs, architecture decision records and key design decisions where integration complexity or reuse potential is significant. Architecture Governance: Provide integration architecture authority into architecture review and Design Authority activity. Ensure material ...

Staff React Full Stack Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
advanced agentic workflows at pace – orchestrating sub‐agents, managing context, running parallel workstreams and embedding AI‐native engineering patterns into everyday delivery. Interpreting our design system to craft beautiful, highly interactive UX workflows from low‐fidelity inputs – you don’t wait for polished Figma to produce polished UI. Inputting … into architecture and technical direction in collaboration with Principal Engineers – making considered, well-reasoned decisions on patterns, frameworks, state management, API design and performance. Championing a high‐quality engineering culture – test coverage, peer review, CI/CD discipline via GitHub Actions, secure coding, accessibility (WCAG) and performance – aligned ...

Senior Software Engineer

Hiring Organisation
Tiro Partners Limited
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£80,000 - £120,000 per annum
Java/Microservices/API design/LLMs/AI/Claude Code/Copilot Role: Senior Software Engineer Company: Financial Services Location: London - Hybrid 3 days per week Salary: up to £120,000 + Benefits Join a newly formed Service Modernisation & AI team driving AI-first software … development tools (e.g. Claude Code, GitHub Copilot, LLMs) Experience with MCP, AI automation, or agentic AI systems Strong understanding of microservices and API design Strong TDD experience Java/Microservices/API design/LLMs/AI/Claude Code/Copilot ...

Senior Product Manager - API Platform

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
Senior) Product Manager - API Platform & Developer Experience Product - API Team Ebury London Office - Hybrid: 4 days in the office, 1 day working from home per week We are looking for a technically strong Senior Product Manager to help grow and evolve our API platform and API … scalable APIs that enable partners and clients to integrate deeply with our payments, FX, and financial services capabilities. You will work closely with engineering, design, and commercial teams to define new endpoints, webhooks, and workflows, while ensuring excellent developer experience and platform reliability. The role sits at the heart ...

Enterprise Architect

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
govern the architecture of the Digital Backbone – the foundational layer that connects systems, data, and services across the enterprise – while driving adoption of API-first principles, integration best practices, and enterprise-wide governance.The Digital Backbone is Howden Group's foundational technology and integration layer, designed to eliminate fragmented systems … manual processes, and to enable digital product delivery and innovation at scale. **WHAT WILL YOU BE DOING?** ## Architecture Leadership & Design* Define, own, and communicate the enterprise architecture of the Digital Backbone, establishing it as the strategic integration platform across Howden Group.* Architect and lead the design, development ...

Enterprise Architect

Hiring Organisation
Jobleads-UK
Location
City Of London, England, United Kingdom
core integration and technology platform, shaping and governing the foundational layer that connects systems, data, and services across the enterprise. Responsibilities Architecture Leadership & Design Define, own, and communicate the enterprise architecture of the Digital Backbone. Architect and lead the design, development, and deployment of APIs and integrations, ensuring … alignment with standards and strategic goals. Drive adoption of API‐first design principles and the APIOps methodology, including automation of API deployment and governance. Develop, maintain, and communicate key architecture artefacts such as policies, standards, principles, patterns, templates, and capability models. Manage Group Enterprise Architecture assets – application ...

Senior Product Manager - API Platform

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
globally, get in touch - we’d love to discuss how Ebury can accelerate your career so you can shape the future. (Senior) Product Manager - API Platform & Developer Experience Product - API Team Ebury London Office - Hybrid: 4 days in the office, 1 day working from home per week … looking for a technically strong Senior Product Manager to help grow and evolve our API platform and API use cases . This role focuses on building high-quality, scalable APIs that enable partners and clients to integrate deeply with our payments, FX, and financial services capabilities. You will ...

Principal Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
architectural coherence to decisions made within individual domains Identify technical risks and compounding complexity before they become incidents Set standards for engineering quality — system design, observability, reliability, API design — that every team builds to Be the senior technical voice in cross‐team planning, roadmap discussions, and major … fast‐moving engineering org — and has the range to show for it Can credibly walk into a conversation about data pipeline architecture, RAG evaluation, API design, or system scalability — and add something useful in all of them Owns problems, not just opinions. You're not here to review ...

Full Stack Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
enjoys working across the whole stack and is equally comfortable building conventional services and AI‐enabled features. Key Responsibilities Build Across the Stack: Design, build and ship features end to end, from APIs and services through to responsive, accessible user interfaces. Cloud Native Delivery: Develop and run cloud‐native … usable, performant ways for brokers and analysts. AI‐Enabled Development: Build AI‐enabled product features using patterns such as retrieval‐augmented generation, tool and API integration, evaluation and human‐in‐the‐loop design. AI‐Assisted Engineering: Use AI‐assisted engineering tools such as Claude Code or Claude Cowork ...

Full Stack Engineer (Contract Role)

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
work alongside architects, product stakeholders and delivery partners to ship software that brokers and analysts use every day.**Key Responsibilities:*** **Build Across the Stack:** Design, build and ship features end to end, from APIs and services through to responsive, accessible user interfaces.* **Cloud Native Delivery:** Develop and run cloud … usable, performant ways for brokers and analysts.* **AI-Enabled Development:** Build AI-enabled product features using patterns such as retrieval-augmented generation, tool and API integration, evaluation and human-in-the-loop design.* **AI-Assisted Engineering:** Use AI-assisted engineering tools such as Claude Code or Claude Cowork ...

Principal C# Engineer / Snr Dev Lead

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
development lead and principal-level C#/.NET engineer within Risk, Product Control and ESG IT. The role combines hands‐on engineering with solution design, stream leadership, technical oversight and delivery accountability across a CTB portfolio. The role will support new product onboarding, feature delivery, methodology changes, platform enhancements … components. The consultant is expected to remain substantially hands‐on, contributing approximately 25%-50% as an individual contributor, with the balance focused on coordination, design governance, mentoring, dependency management and delivery execution. The technology stack is primarily C#/.NET, supported by MongoDB, SQL Server data warehouse components, enterprise ...

Python Technical Lead FinTech

Hiring Organisation
Run-Time Group Ltd
Location
City of London, London, United Kingdom
Employment Type
Permanent
major advantage. Key Responsibilities Technical Leadership Own the technical roadmap, guide architectural decisions, and ensure engineering excellence across backend services. Python Engineering Design and build robust, secure, and scalable microservices using Python (FastAPI, Django, Flask). System Architecture Lead the design of distributed systems, event-driven architectures … data intelligence. DevOps & Cloud Collaborate on CI/CD pipelines, containerisation (Docker, Kubernetes), and cloud deployments (AWS/GCP/Azure). Data & API Strategy Oversee API design, data modelling, and integration with internal and external financial systems. Security & Compliance Ensure systems meet regulatory, security, and audit ...

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 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 ...

Senior Full Stack/Native Cloud Engineer (Vice President)

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

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 ...

AWS Solution Architect (Senior Manager)

Hiring Organisation
Anson Mccade
Location
City of London, London, United Kingdom
Employment Type
Permanent
high-performing cloud practice. This is an opportunity to work at the forefront of cloud transformation, partnering with tier-one clients across industries to design and deliver innovative, scalable, and secure AWS solutions. Youll play a pivotal role in shaping enterprise cloud strategies while leading complex transformation programmes. … strategy Certifications & Education AWS Certification (Associate or Professional e.g. Solutions Architect, DevOps Engineer) Degree in Computer Science, Engineering, or related discipline Technical Expertise Architecture & Design Translating business needs into scalable cloud architectures Cost optimisation and cloud best practices Data & AI Experience with data platforms, analytics, and AI/ ...

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 ...

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 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 ...

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 ...

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

Hiring Organisation
Fruition Group
Location
City of London, London, United Kingdom
Employment Type
Permanent
Salary
£90,000
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 ...