26 to 50 of 280 API Design Jobs in London

frontend developer for business planning

Location
Greater London, England, United Kingdom
Build and maintain user interfaces for client-facing features, ensuring high-quality and performant UI delivery Collaborate with backend engineers and product managers to design, develop, and deliver new features while providing technical input on API design and data handling Implement and enhance AI-driven capabilities that … with complex workflows Develop advanced data visualizations, including charts, maps, and dashboards, that provide real-time interactive insights Contribute to and maintain the internal design system, including custom caching mechanisms and advanced state management solutions Balance new feature delivery with ongoing maintenance and performance optimization Identify and resolve issues ...

Senior Software Engineer

Hiring Organisation
The Portfolio Group
Location
City of London, London, United Kingdom
Employment Type
Permanent
Salary
£90000/annum
integration layer behind a new generation of AI-powered products. This is a genuinely full-stack engineering role, combining production-grade backend development, API design, AI integrations and frontend engineering. You'll work across the full application lifecycle, designing the services and interfaces that connect AI capabilities … products customers and colleagues use every day. You'll play a key role in building MCP integrations, agent-to-agent connectivity and robust API services, while also developing responsive, accessible interfaces in React and TypeScript. What you'll be doing Own the application and integration layer of AI products ...

Senior Software Engineer

Hiring Organisation
The Portfolio Group
Location
London, South East England, United Kingdom
Employment Type
Full-Time
Salary
£90,000 per annum
integration layer behind a new generation of AI-powered products. This is a genuinely full-stack engineering role, combining production-grade backend development, API design, AI integrations and frontend engineering. You'll work across the full application lifecycle, designing the services and interfaces that connect AI capabilities … products customers and colleagues use every day. You'll play a key role in building MCP integrations, agent-to-agent connectivity and robust API services, while also developing responsive, accessible interfaces in React and TypeScript. What you'll be doing Own the application and integration layer of AI products ...

Senior Software Development Engineer

Hiring Organisation
Expedia
Location
London, United Kingdom
Salary
£ 80 K
solvers with a growth mindset. We value our team culture and work together from the office three times a week.In this role, you will:Design, build, and maintain robust full stack applications and scalable services across multiple domains, applying deep technical expertise and architectural skills.Lead … development process, including system design, API design, and data modelling, ensuring quality and maintainability of solutions.Collaborate across engineering, product, and business teams to define requirements, deliver impactful features, and drive technology strategy.Mentor and guide engineers, fostering best practices in coding, testing, and operational excellence within and across ...

Senior .NET Architect: Microservices & API Design

Location
Greater London, England, United Kingdom
Limited is seeking a senior .NET Architect to lead the architecture of .NET-based applications, including .NET Core/ASP.NET MVC, C#, and Web API 2. You will define the overall structure, components, and interactions to support scalable, reliable systems. This role involves API design, data exchange ...

Backend Developer (Azure)

Hiring Organisation
Amtis Professional Ltd
Location
London, Euston, United Kingdom
Employment Type
Contract
Contract Rate
£425 - £475/day OUTSIDE IR35
outside IR35. This is a hands-on role working on a mature Azure-based backend platform, with responsibility across the full software lifecycle - from design and development through to testing, deployment and production support. You’ll be working with C#, .NET, Azure Functions, Azure SQL, Azure Service Bus, Azure … API Management and Azure DevOps, contributing to a platform that supports connected patient services. This role is particularly suited to a developer who can hit the ground running, work independently and own technical delivery end-to-end without requiring day-to-day technical supervision. What You’ll Be Doing ...

Backend Developer (Azure)

Hiring Organisation
Amtis professional Ltd
Location
London, South East England, United Kingdom
Employment Type
Full-Time
Salary
£425.00 - £475.00 per day
outside IR35. This is a hands-on role working on a mature Azure-based backend platform, with responsibility across the full software lifecycle - from design and development through to testing, deployment and production support. You’ll be working with C#, .NET, Azure Functions, Azure SQL, Azure Service Bus, Azure … API Management and Azure DevOps, contributing to a platform that supports connected patient services. This role is particularly suited to a developer who can hit the ground running, work independently and own technical delivery end-to-end without requiring day-to-day technical supervision. What You’ll Be Doing ...

Product Manager – Global Card Issuing Platform (BaaS)

Hiring Organisation
WorldFirst
Location
London, United Kingdom
Salary
£ 80 K
grade infrastructure that allows clients to launch card programs anywhere in the world through a single integration.You will be responsible for a unified Global API and SDK suite that abstracts the complexity of regional payment networks. Whether a client is launching in Europe, North America, or APAC, your product … will provide a consistent, white-label experience. You will drive both the technical "how" (API/SDK design) and the strategic "where" (global expansion and regional issuing setups).What you’ll do:Unified Global API Strategy: Design and maintain a single, polymorphic API architecture that ...

backend developer for developer documentation

Location
Greater London, England, United Kingdom
code reviews, pair programming, and architecture discussions; Collaborate cross-functionally with other Apple teams to integrate tools and systems seamlessly; Write detailed architecture and design proposals; Identify areas for continuous improvement; Mentor other engineers; Contribute to architecture discussions, code reviews, and proposals. Требования Experience shipping high-quality, performant … reliable web applications; Passion for developing products and features; Ability to discuss technical trade-offs across system architecture, database design, API design, and infrastructure; Continuous learning attitude focused on improving personal and team capabilities; Nice to have: BS/MS in Computer Science, Computer Engineering, Informatics ...

Java API Developer, Assistant Vice President

Hiring Organisation
State Street Bank
Location
London, United Kingdom
Salary
£ 80 K
DescriptionRole Summary :We are seeking an experienced Java API Developer to join our Digital Asset development team. This is a hands‐on engineering role responsible for building and operating secure, resilient API services that power institutional digital asset capabilities—spanning digital custody, tokenization enablement, digital transfer agency … will work closely with cross-functional teams to build robust, scalable, and secure digital asset products that meet our business and technical requirements.Role Description:Design, develop, and maintain Java backend services and REST APIs that support digital asset product flows (custody, tokenization, TA, digital cash/settlement) and integrate ...

Full Stack Engineer

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 ...

Enterprise Software Architect

Location
Bromley, England, United Kingdom
enterprise and partner ecosystems. The position also plays a key role in shaping industry best practices and representing the organisation externally. Enterprise & Ecosystem Architecture Design and oversee the implementation of enterprise‐wide software architecture, spanning internal platforms, cloud environments, and external partner ecosystems Develop “big picture” architectural frameworks … adherence to security, compliance, regulatory, and quality standards Identify and mitigate long‐term architectural risks (e.g., vendor lock‐in, scalability constraints, regulatory exposure) Technical Design & Solution Development Conduct research, analyse data, gather requirements, and define end‐to‐end solutions Create architectural artefacts representing system functions, integrations, and user interfaces ...

Senior Java Developer

Hiring Organisation
CODEVERSE LIMITED
Location
London, South East England, United Kingdom
Employment Type
Full-Time
Salary
£300.00 - £400.00 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 ...

Java API Developer, Officer

Hiring Organisation
State Street Bank
Location
London, United Kingdom
Salary
£ 80 K
Role Summary :We are seeking a Java API Developer to join our Digital Asset development team. This is a hands-on software engineering role responsible for designing, developing, testing, and supporting RESTful APIs and backend services in a financial services environment. The role contributes to building reliable, secure … will work closely with cross-functional teams to build robust, scalable, and secure digital asset products that meet our business and technical requirements.Role Description :Design, develop, and maintain Java-based backend services and REST APIs that support financial services workflows and data use cases.Implement APIs in line with internal ...

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 ...

Java API Developer, Officer

Hiring Organisation
State Street Bank
Location
London, UK
Employment Type
Full-time
Role Summary :We are seeking a Java API Developer to join our Digital Asset development team. This is a hands-on software engineering role responsible for designing, developing, testing, and supporting RESTful APIs and backend services in a financial services environment. The role contributes to building reliable, secure … work closely with cross-functional teams to build robust, scalable, and secure digital asset products that meet our business and technical requirements. Role Description :Design, develop, and maintain Java-based backend services and REST APIs that support financial services workflows and data use cases. Implement APIs in line with ...

Senior Data Architect

Hiring Organisation
SIX Group
Location
London, United Kingdom
Salary
£ 80 K
across the firm to ensure our data products deliver value to our customers and they can be readily maintained and enhanced. This encompasses the design and architecture of logical and physical data models and schemas, data transport mechanisms, metadata management, lineage management, API schema design and enabling … financial information to be accessible to AI agents.What You Will Do • Design, develop and maintain the technology-agnostic, business-aligned canonical/conceptual data models for Financial Information, defining class definitions, standards and association semantics.• Provide data architecture expertise to all delivery teams to ensure we build data products ...

Senior Full Stack/Native Cloud Engineer (Vice President)

Hiring Organisation
Jefferies Financial Group
Location
London, United Kingdom
Salary
£ 100 K
full technology stack, from backend services and distributed data architecture through to responsive user interfaces, production support, and engineering best practice.Key ResponsibilitiesLead 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, and Amazon ...

Senior Manager- Software Engineering

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 ...

frontend js/react/typescript for AI video platforms

Location
Greater London, England, United Kingdom
used by over 90% of the Fortune 100, and its proprietary generative AI technology is built in-house. Задачи: Build, scale and evolve the design system, including the component library, design tokens and documentation Extend the design system for AI-assisted development using Storybook and machine-readable … interfaces such as MCP Design component APIs that resist misuse by AI and human developers Write high-quality, performant frontend code with React and TypeScript Partner with design, product and engineering to define components and deliver production-ready solutions Make components accessible by default according to WCAG 2.2 ...

Manager - Lead AI Engineer

Hiring Organisation
KPMG UK
Location
London Area, United Kingdom
Data Analytics, and Software Development, the team is revolutionising the auditing process to deliver smarter, faster, and more reliable outcomes. Our mission is to design and implement robust, intelligent, and scalable technologies that not only streamline workflows but also enhance audit quality and generate actionable insights for auditors … backend development as a Senior role. Languages/Frameworks: Strong proficiency in Python with hands-on experience in asynchronous programming, concurrency and multithreading. API Expertise: Proven experience in building and integrating APIs, with expertise in API documentation and schema definition using OpenAPI/Swagger. Strong understanding of RESTful ...

Solution Architect

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 ...

Senior Software Engineer

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

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\". ...

Senior Software Engineer | API Enterprise | Full-Stack

Hiring Organisation
DeepL
Location
London, United Kingdom
Salary
£ 80 K
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-service … 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." We don't hire ...