201 to 225 of 308 API Design Jobs in London

Lead Software Engineer - Umbraco

Location
London, United Kingdom
designing and implementing APIs and integrations within complex digital ecosystems, including CRM, payment and marketing platforms. Database and data management. Strong expertise in database design and efficient querying in the context of web applications. Cloud and deployment. Practical experience with cloud platforms and managed hosting, particularly Azure and Umbraco … .NET practice Umbraco Cloud, or equivalent managed hosting experience, including environment strategy and deployment workflow Major version upgrade planning and delivery on live platforms API design and consumption, REST and GraphQL, including third-party integrations SQL Server and efficient data querying in a web application context Modern front ...

Junior Software Developer

Location
Greater London, England, United Kingdom
frontend) and Node.js (backend). Build and integrate backend services and APIs using Python with a web framework (e.g. Django, Flask, or FastAPI). Design, query, and manage relational and NoSQL databases (PostgreSQL, SQL, MongoDB). Work on machine learning tasks including object detection, model training, and deployment. Deploy … detection, model training, and deployment (not just coursework or personal projects). Cloud: Basic working knowledge of AWS. Nice to have Exposure to REST API design and integration. Familiarity with version control (Git). Understanding of basic DevOps or CI/CD concepts. Role details Job title: Junior ...

AI Engineer

Hiring Organisation
Oscar Associates (UK) Limited
Location
London, United Kingdom
Employment Type
Permanent
Hybrid Build the AI systems our users actually experience. We're looking for a dynamic AI Engineer (5+ years) to design, build, and deploy autonomous, user-facing AI solutions - LLM-powered applications, agentic workflows, and intelligent systems that perform reliably at scale, not just in a demo. What … Degree in Computer Science (or equivalent) with strong AI/ML/NLP foundations Strong Python skills, familiarity with Java/Kotlin, and solid API design experience Hands-on experience with LangChain, LangGraph, and LLM APIs (OpenAI, Anthropic, etc.) Skilled in prompt engineering and orchestrating AI agents/ ...

Staff Product Manager, GTPN

Hiring Organisation
Airwallex
Location
London, UK
Employment Type
Full-time
Staff Product Manager, GTPN (Global Treasury & Payment Network), you will drive the strategy, roadmap, and execution for our customer-facing API platform, enabling global treasury and payment solutions at scale. You will work cross-functionally with engineering, sales, and leadership to deliver innovative, scalable, and secure API products … validate product features. Translate complex use cases into scalable, secure, and intuitive APIs in collaboration with engineering teams. Lead cross-functional teams—including engineering, design, sales, compliance, and data science—to deliver impactful solutions. Use data-driven methods to define and measure success metrics, prioritize requirements, and communicate plans ...

Mid-level Backend Engineer

Location
Greater London, England, United Kingdom
regulatory burdens. We serve Tier 1 banks across Europe, North America, and Asia. We are looking for a Mid‐level Backend Engineer to help design, build, and scale our regulatory reporting platform. You’ll own features end‐to‐end — collaborating directly with product to shape requirements, and with … week. Some travel may be required. Suade is an equal opportunity employer. All qualified applicants will receive consideration for employment without bias. Responsibilities Design, build, and ship features independently, from technical design through deployment Maintain and lead the improvement of existing features within the application Write efficient, well ...

Power Platform Architect

Location
Greater London, England, United Kingdom
applications. Define and maintain reference architectures, principles, standards and reusable patterns while managing security, data, accessibility, operational and lifecycle risks. Chair or lead proportionate design assurance, record significant decisions and ensure exceptions, risks, technical debt and dependencies have clear owners and treatment plans. Advise leaders on architectural options, benefits … coaching architects and enhancing architecture practices within multidisciplinary environments. Highest-signal resume keywords Technical Architecture Leadership Microsoft Power Platform Expertise Cloud-Based Application Ecosystem Design Architecture Governance and Risk Management Coaching and Professional Development ATS Optimization Keywords Hard Skills Technical Direction Setting Architecture Governance Cloud Architecture API Design ...

Software Engineer (Backend)

Location
Greater London, England, United Kingdom
writing readable, testable, and maintainable code. Solid programming skills in at least one backend language (Elixir, C++, Python, Ruby etc). Strong understanding in API design (RESTful or GraphQL). Good understanding in SQL. Willingness to learn new languages/technologies. These are our ideal requirements ...

Senior Product Engineer (£80k-125k + Equity)

Location
Greater London, England, United Kingdom
lead frontend architecture in React and TypeScript, set the quality bar for components, state management, and performance. And you don't stop there. From API design to cloud infrastructure (AWS), you ship complete, polished features end to end, including AI-powered ones built on LLM APIs, prompt engineering ...

Engineering Team Lead - 12 month FTC

Location
Greater London, England, United Kingdom
than on a purely backend squad. Strong commercial C#/.NET experience, with a solid grasp of SOLID, event‐driven architecture and DDD RESTful API design and SQL skills Cloud‐native Azure development Enough frontend fluency to review React/TypeScript work, even if you're not hands ...

Senior Python Engineer: AI Agents & Forecasting

Location
Greater London, England, United Kingdom
LangChain or LangGraph (agent memory, tool calling, state management) Dagster in production (assets, sensors, partitions) or equivalent pipeline orchestration Strong backend fundamentals including API design, async programming, and database modelling You've built systems that had to work reliably at scale, not just pass a demo Experience 5+ ...

Scala Engineer

Location
City Of London, England, United Kingdom
Responsibilities Help define and deliver the future vision for attribute reputation services, driving simplification and consolidation where appropriate. Design and develop high-volume, high-availability, low-latency backend services. Enhance and optimise existing applications and services. Support incremental re-architecting initiatives to reduce technical complexity and improve maintainability. Develop … clean, testable and maintainable code using Scala and modern engineering practices. Design, build and maintain secure APIs, databases and applications. Collaborate with Product Owners, Business Analysts, Data Engineers and wider technical teams to deliver effective software solutions. Contribute to service support and operational excellence within a "build ...

Lead ML Engineer

Location
Greater London, England, United Kingdom
strong emphasis on defining the future product and platform experience, patterns, and contribution pathways that will enable federated scale over time.ML Engineers – Responsibilities & SkillsResponsibilities\* Design and build MCP servers and tools that expose enterprise systems and workflows to AI agents.\* Implement Skills that orchestrate tools, data, and reasoning into … repeatable, governed workflows.\* Contribute to the LSEG AI Assist agentic harness, including planning, tool‐calling, and orchestration logic.\* Build secure API wrappers where backend systems lack suitable authentication or entitlement models.\* Work closely with product teams in a “build for” capacity, transferring knowledge and establishing reusable patterns.\* Shape ...

IAM Product Engineer

Location
Greater London, England, United Kingdom
stability. Your responsibilities will be varied and impactful, offering a dynamic and challenging work environment. A fundamental aspect of this position is the design and construction of robust, scalable, and high-performing code. You will be instrumental in building the platform that opens the door to all our current … experience. You are a collaborative Software Engineer with proven professional experience in Javascript/Typescript , React , and Node.JS , you possess a strong understanding of API design , consumption, and client-side logic. You are proficient in writing unit and integration tests and have experience with NoSQL databases like Mongo ...

Senior Fullstack Engineer, Scale

Hiring Organisation
Airwallex
Location
London, UK
Employment Type
Full-time
regulatory, and technical domains—areas where no single existing team has full coverage, like tax systems, compliance-driven flows, or monetization tools. Solutions Architecture: Design integrations for enterprise prospects by translating their business requirements into technical solutions. Your architectural decisions directly influence deal outcomes—from enabling multi-million dollar … technical stakeholdersMake pragmatic decisions on when to optimize for performance vs. velocity based on business impactThrive in cross-functional environments spanning Product, Design, Compliance, and SalesDesign for scale, maintainability, and production excellencePreferred qualifications: Fintech, payments, or regulated industry experienceHigh-scale performance tuning (100k+ QPS, large user bases, strict latency ...

Backend Engineer London

Location
Greater London, England, United Kingdom
each play a role in shaping Augur's product, value to customers and culture as we grow. We are looking for someone who can design and build the distributed systems, storage infrastructure, and platform primitives that underpin Augur's sensor integration product. You'll work across the full backend … surface: from stream processing and storage, to API design, data pipelines, and service architecture, in a Rust stack with Python at the platform API boundaries. You’ll be responsible for building robust, well-abstracted systems that scale with the demands of a growing integration and customer base ...

Principal Software Engineer - C#

Location
City Of London, England, United Kingdom
Role Overview ICRV are seeking an exceptional Principal Engineer to own the architecture, design and hands‐on delivery of a desktop platform automating and streamlining trading desk workflows. This is a high‐visibility player‐coach role that may evolve to include formal people management. Role Responsibilities … output. Own the technical direction of the ICRV greenfield project, developing high‐performance, scalable, and robust solutions from first principles through to production operation. Design for hard non‐functional requirements: latency and responsiveness budgets as acceptance criteria, crash containment, least‐privilege isolation between sub‐applications. Work effectively with ...

Lead Software Engineer, Team Lead

Hiring Organisation
Marsh & McLennan Companies
Location
London, UK
Employment Type
Full-time
products (e.g., Concierge an agentic AI workflow tool, Prism a Mercer knowledge fabric for scheme data, and similar initiatives), from problem framing and design through build, release, and support. Translate risk advisory/consulting needs into clear technical requirements, user stories, and solution designs; partner with stakeholders through … Proven experience as a Tech Lead/Lead Engineer delivering production software, including hands-on coding and code review ownership. Strong backend engineering skills (API design, data modelling, performance) and experience building secure, role-based applications. Experience working directly with business stakeholders in a financial firm, with ...

Agent Runtime & Systems - Member of Technical Staff

Location
Greater London, England, United Kingdom
model and tool footprint. This is a high-leverage role tackling complex systems challenges across the entire stack. Runtime, observability tooling, and framework design are three separate specialties. We are glad to hire someone with real depth in a combination of them. What You’ll Build Design … handoffs, state changes, and runtime decisions Develop clear Python APIs, libraries, and DSLs with stable extension points for tools, backends, and new execution models Design scheduling, placement, backpressure, resource accounting, sandboxing, permissions, and isolation for secure tool execution at scale Develop tooling for trajectory collection and visualisation, performance profiling ...

Principal Software Engineer - C#

Hiring Organisation
Liquidnet
Location
London, UK
Employment Type
Full-time
that executes complex, multi-leg synthetic strategies on behalf of institutional clients. Role OverviewICRV are seeking an exceptional Principal Engineer to own the architecture, design and hands-on delivery of desktop platform automating and streamlining trading desk workflows. This is a high-visibility player-coach role: you will apply … output. Own the technical direction of the ICRV greenfield project, developing high-performance, scalable, and robust solutions from first principles through to production operation. Design for hard non-functional requirements: latency and responsiveness budgets as acceptance criteria, crash containment, least-privilege isolation between sub-applications. Work effectively with ...

Principal Software Engineer - C#

Location
Greater London, England, United Kingdom
executes complex, multi-leg synthetic strategies on behalf of institutional clients.**Role Overview**ICRV are seeking an exceptional Principal Engineer to own the architecture, design and hands-on delivery of desktop platform automating and streamlining trading desk workflows. This is a high-visibility player-coach role: you will apply … output.* Own the technical direction of the ICRV greenfield project, developing high-performance, scalable, and robust solutions from first principles through to production operation.* Design for hard non-functional requirements: latency and responsiveness budgets as acceptance criteria, crash containment, least-privilege isolation between sub-applications.* Work effectively with ...

Game Developer

Location
Greater London, England, United Kingdom
heart of immersive, physical learning and play. You implement the game formats designed by our content team, in close partnership with our engineering and design teams. You combine our many device capabilities to make delightful, surprising experiences: Using audio, voice, display, light, haptics, and sensing of physical objects. … company to be the place where you do your best work: With autonomy, curiosity, optimism, and playfulness. What You’ll Work On Experience Design and Implementation Implement the game formats and experiences our content team designs Turn rough prototypes into robust, replayable experiences Design abstractions that allow ...

Software Development Engineer II

Location
Greater London, England, United Kingdom
best out of them and we'll look to you to apply good judgement on what lands in main.In this role, you will:Design, build, test, and maintain reliable software components that deliver high-quality customer and business outcomes.Translate product and technical requirements into maintainable solutions, applying sound engineering … role.Experience owning and delivering features or components within a service or defined technical area.Proficiency in software development fundamentals, including coding, testing, debugging, version control, API design, data modeling, and low-level system design.Experience working with cross-functional partners to deliver, operate, and improve production software.Preferred Qualifications:Experience designing ...

Applied Value Engineer

Hiring Organisation
Celonis
Location
London, UK
Employment Type
Full-time
finance). Ability to speak the language of business leaders and connect operational bottlenecks to strategic AI solutions. Software/Data Engineering: Python proficiency, API design, SQL, data integration, and ML/AI libraries (PyTorch, TensorFlow, scikit-learn, XGBoost, Hugging Face Transformers).Agentic AI Systems: Hands-on experience … Earth Is Our Future—drive every decision. About Us: Celonis is the trusted platform to industrialize Enterprise AI, empowering organizations to analyze, design, and operate AI-driven processes. The Celonis Platform is powered by the Celonis Context Model, which combines process data, business knowledge, and intelligence to create ...

Principal Software Engineer - C#

Location
City Of London, England, United Kingdom
team that executes complex, multi-leg synthetic strategies on behalf of institutional clients.Role OverviewICRV are seeking an exceptional Principal Engineer to own the architecture, design and hands-on delivery of desktop platform automating and streamlining trading desk workflows. This is a high-visibility player-coach role: you will apply … C#/.NET (LTS): back-end services with ASP.NET Core.Experience designing and delivering event-driven, service-oriented back-end systems (message brokers, async workflows, API design) in a production trading environment.Experience building desktop applications that host web content (e.g., Electron, Tauri, or custom .NET host); comfortable with WebSocket ...

Senior Frontend & Fullstack UI Engineer (Hybrid, London)

Location
Greater London, England, United Kingdom
Software Engineer with senior-level expertise to architect and implement scalable, secure frontend and fullstack platforms. You will lead architecture decisions, drive design system adherence, and mentor teams across the software delivery lifecycle. The role focuses on modern frontend tech such as React/TypeScript, API design ...