26 to 50 of 87 API Design Jobs in London

Fullstack Engineer, you will be pivotal in both frontend and backend development, crafting responsive, scalable web applications. This role requires strong expertise across the stack — from UI/UX design principles to backend integrations. You will design and implement APIs using JavaScript, TypeScript, and React, ensuring seamless performance and scalability. We’re looking for a proactive and experienced … and enjoys leading complex projects from conception to delivery. You’ll be both a technical leader and a driver of innovation across the team. Key Responsibilities Data Pipeline Architecture Design and implement robust, scalable data pipelines. Optimise data flow between databases (MySQL, MongoDB) and applications. Fullstack Development Develop high-quality, scalable applications using Node.js, TypeScript, and React. Collaborate with … frameworks and state management libraries like Redux or Context API. Hands-on experience with cloud services (AWS or GCP), particularly for deploying and managing applications0. Strong understanding of RESTful API design (GraphQL experience a plus). Analytical mindset with the ability to design, optimise, and troubleshoot complex UIs and fullstack integrations. Excellent communication and leadership skills with More ❯

standard Back End role. We are seeking a foundational engineer to own our single greatest strategic asset: our unique, privileged access to network-level intelligence via the GSMA CAMARA API standard. This is our right to win, and you will be the engineer responsible for building the bridge to it. You will be the Critical Path Owner for Track … Key Responsibilities Telco Integration & Architecture Own and build the Security Signal Ingestion path, the secure, low-latency, and out-of-band data channel connecting to our founding members' network API gateways. Architect and implement a carrier-agnostic, vendor-agnostic connector layer to consume RESTful APIs from a heterogeneous global landscape of telco partners and IMS vendors (eg, Nokia, Ericsson … technical liaison to the engineering teams at our telco founders (Deutsche Telekom, Singtel, SKT, etc.), working hand-in-glove to navigate, validate, and productionize their new CAMARA network APIs. Design and build the high-throughput microservices that will query, ingest, normalize, and cache network signals (eg, sim-swap, device-roaming-status) to be used in our Real Time Scam More ❯

a standard backend role. We are seeking a foundational engineer to own our single greatest strategic asset: our unique, privileged access to network-level intelligence via the GSMA CAMARA API standard. This is our right to win, and you will be the engineer responsible for building the bridge to it. You will be the Critical Path Owner for Track … Key Responsibilities Telco Integration & Architecture ? Own and build the Security Signal Ingestion path, the secure, low-latency, and out-of-band data channel connecting to our founding members' network API gateways. ? Architect and implement a carrier-agnostic, vendor-agnostic connector layer to consume RESTful APIs from a heterogeneous global landscape of telco partners and IMS vendors (e.g., Nokia, Ericsson … technical liaison to the engineering teams at our telco founders (Deutsche Telekom, Singtel, SKT, etc.), working hand-in-glove to navigate, validate, and productionize their new CAMARA network APIs. ? Design and build the high-throughput microservices that will query, ingest, normalize, and cache network signals (e.g., sim-swap, device-roaming-status) to be used in our real-time Scam More ❯

from home Role Overview A key client of ours in the media space are seeking an experienced Senior Full Stack Web Developer to play a key role in the design, development, and delivery of innovative, high-performance web applications. This position is central to the ongoing evolution of our programmatic and data-driven integration platforms, with a focus on … across multiple environments. This is an opportunity to work in a collaborative, fast-moving environment where technical expertise, creative problem-solving, and continuous improvement are highly valued. Key Accountabilities Design, develop, and maintain scalable and secure software applications aligned with architectural and business objectives. Partner with business, technical, and product leaders to deliver solutions that support the company's … strategic vision. Champion best practices in coding standards, testing, deployment, and DevOps automation. Contribute to a culture of innovation, collaboration, and continuous technical improvement. Key Responsibilities Lead the design and development of dynamic, responsive web applications using React.js , Node.js , and related technologies. Build and optimize PostgreSQL databases, including schema design, complex queries, and performance tuning. Implement and manage More ❯

including: TypeScript/JavaScript (NextJS, NodeJS, Tailwind) Python (Django, Flask, or FastAPI) PostgreSQL Experience with building and scaling SaaS platforms in production. Strong background in software architecture, microservices, and API design. Hands-on experience with cloud platforms (AWS, Azure, or GCP). Excellent communication skills, capable of motivating and aligning technical teams. Desirable: Experience with AI tools, APIs, ML More ❯

including: TypeScript/JavaScript (NextJS, NodeJS, Tailwind) Python (Django, Flask, or FastAPI) PostgreSQL Experience with building and scaling SaaS platforms in production. Strong background in software architecture, microservices, and API design. Hands-on experience with cloud platforms (AWS, Azure, or GCP). Excellent communication skills, capable of motivating and aligning technical teams. Desirable: Experience with AI tools, APIs, ML More ❯

reflects the great diversity of our real customers and users across the world. What You’ll Do Own our engineering stack from MVP to scale — backend, frontend, infra . Design architecture, choose tools, and set engineering standards. Work directly with early users to iterate quickly. Collaborate with the founding team on strategy, hiring, and scaling the tech team. Ship … high-quality, user-focused features (that change Oceans and planet) fast. What We’re Looking For 5+ years of backend expertise in Go including API design, microservices architecture, gRPC/REST services, and database design (PostgreSQL, Redis). Frontend proficiency with React/Next.js, responsive design, and modern JavaScript/TypeScript Cloud infrastructure knowledge including AWS … and opportunity. Expert in solving deep technical problems with customer outcomes top of mind. Ability to evaluate and make decisions based on a balanced assessment of key factors, including design, scalability, performance, technical debt and cost efficiency. Working highly collaboratively in a team environment. What We Offer Professional Impact & Growth Build a high-impact platform from emerging MVP to More ❯

reflects the great diversity of our real customers and users across the world. What You’ll Do Own our engineering stack from MVP to scale — backend, frontend, infra . Design architecture, choose tools, and set engineering standards. Work directly with early users to iterate quickly. Collaborate with the founding team on strategy, hiring, and scaling the tech team. Ship … high-quality, user-focused features (that change Oceans and planet) fast. What We’re Looking For 5+ years of backend expertise in Go including API design, microservices architecture, gRPC/REST services, and database design (PostgreSQL, Redis). Frontend proficiency with React/Next.js, responsive design, and modern JavaScript/TypeScript Cloud infrastructure knowledge including AWS … and opportunity. Expert in solving deep technical problems with customer outcomes top of mind. Ability to evaluate and make decisions based on a balanced assessment of key factors, including design, scalability, performance, technical debt and cost efficiency. Working highly collaboratively in a team environment. What We Offer Professional Impact & Growth Build a high-impact platform from emerging MVP to More ❯

reflects the great diversity of our real customers and users across the world. What You’ll Do Own our engineering stack from MVP to scale — backend, frontend, infra . Design architecture, choose tools, and set engineering standards. Work directly with early users to iterate quickly. Collaborate with the founding team on strategy, hiring, and scaling the tech team. Ship … high-quality, user-focused features (that change Oceans and planet) fast. What We’re Looking For 5+ years of backend expertise in Go including API design, microservices architecture, gRPC/REST services, and database design (PostgreSQL, Redis). Frontend proficiency with React/Next.js, responsive design, and modern JavaScript/TypeScript Cloud infrastructure knowledge including AWS … and opportunity. Expert in solving deep technical problems with customer outcomes top of mind. Ability to evaluate and make decisions based on a balanced assessment of key factors, including design, scalability, performance, technical debt and cost efficiency. Working highly collaboratively in a team environment. What We Offer Professional Impact & Growth Build a high-impact platform from emerging MVP to More ❯

reflects the great diversity of our real customers and users across the world. What You’ll Do Own our engineering stack from MVP to scale — backend, frontend, infra . Design architecture, choose tools, and set engineering standards. Work directly with early users to iterate quickly. Collaborate with the founding team on strategy, hiring, and scaling the tech team. Ship … high-quality, user-focused features (that change Oceans and planet) fast. What We’re Looking For 5+ years of backend expertise in Go including API design, microservices architecture, gRPC/REST services, and database design (PostgreSQL, Redis). Frontend proficiency with React/Next.js, responsive design, and modern JavaScript/TypeScript Cloud infrastructure knowledge including AWS … and opportunity. Expert in solving deep technical problems with customer outcomes top of mind. Ability to evaluate and make decisions based on a balanced assessment of key factors, including design, scalability, performance, technical debt and cost efficiency. Working highly collaboratively in a team environment. What We Offer Professional Impact & Growth Build a high-impact platform from emerging MVP to More ❯

generation Unified Client Experience (UCX) frontend that will streamline client journeys across a range of products and services, in both web and mobile domains. It's an opportunity to design, architect and build a modern frontend using latest technologies and best practices to transform our savings and investment platform. The UCX team consolidates the efforts of the whole organisation … scale, regulated environments - ideally in Investment, Asset or Wealth Management. Solid experience in building and deploying frontend applications in React or React Native with hands-on knowledge of secure API design and authentication services. Experience in Java and Spring Boot, or iOS (Swift) or Android (Kotlin) along with exposure to Figma and Vercel is a big plus. Capable More ❯

Engineer will be responsible for both frontend and backend development, ensuring seamless integration and high performance of web applications. Responsibilities Lead technical initiatives and projects, ensuring high-quality delivery. Design and implement complex software applications, emphasizing robust and scalable solutions. Collaborate with cross-functional teams to define, design, and ship new features. Ensure code quality and maintainability through … code reviews and adherence to design patterns. Optimize the performance of web applications to ensure fast and efficient user experiences. Mentor junior engineers and promote a culture of continuous learning and improvement. Address and refactor legacy code, bringing it up to modern standards and practices. Drive changes in coding practices and standards to improve code quality and team efficiency. …/large-sized projects, particularly in single-page applications (SPA) or back-office systems. Experience in optimizing the performance of web applications. Strong knowledge of software engineering principles and design patterns. Understanding of backend technologies, including Node.js, Express, or similar frameworks. 5+ years preferred. Experience with RESTful API design and development. Familiarity with database management systems such More ❯

Engineer will be responsible for both frontend and backend development, ensuring seamless integration and high performance of web applications. Responsibilities Lead technical initiatives and projects, ensuring high-quality delivery. Design and implement complex software applications, emphasizing robust and scalable solutions. Collaborate with cross-functional teams to define, design, and ship new features. Ensure code quality and maintainability through … code reviews and adherence to design patterns. Optimize the performance of web applications to ensure fast and efficient user experiences. Mentor junior engineers and promote a culture of continuous learning and improvement. Address and refactor legacy code, bringing it up to modern standards and practices. Drive changes in coding practices and standards to improve code quality and team efficiency. …/large-sized projects, particularly in single-page applications (SPA) or back-office systems. Experience in optimizing the performance of web applications. Strong knowledge of software engineering principles and design patterns. Understanding of backend technologies, including Node.js, Express, or similar frameworks. 5+ years preferred. Experience with RESTful API design and development. Familiarity with database management systems such More ❯

Engineer will be responsible for both frontend and backend development, ensuring seamless integration and high performance of web applications. Responsibilities Lead technical initiatives and projects, ensuring high-quality delivery. Design and implement complex software applications, emphasizing robust and scalable solutions. Collaborate with cross-functional teams to define, design, and ship new features. Ensure code quality and maintainability through … code reviews and adherence to design patterns. Optimize the performance of web applications to ensure fast and efficient user experiences. Mentor junior engineers and promote a culture of continuous learning and improvement. Address and refactor legacy code, bringing it up to modern standards and practices. Drive changes in coding practices and standards to improve code quality and team efficiency. …/large-sized projects, particularly in single-page applications (SPA) or back-office systems. Experience in optimizing the performance of web applications. Strong knowledge of software engineering principles and design patterns. Understanding of backend technologies, including Node.js, Express, or similar frameworks. 5+ years preferred. Experience with RESTful API design and development. Familiarity with database management systems such More ❯

Engineer will be responsible for both frontend and backend development, ensuring seamless integration and high performance of web applications. Responsibilities Lead technical initiatives and projects, ensuring high-quality delivery. Design and implement complex software applications, emphasizing robust and scalable solutions. Collaborate with cross-functional teams to define, design, and ship new features. Ensure code quality and maintainability through … code reviews and adherence to design patterns. Optimize the performance of web applications to ensure fast and efficient user experiences. Mentor junior engineers and promote a culture of continuous learning and improvement. Address and refactor legacy code, bringing it up to modern standards and practices. Drive changes in coding practices and standards to improve code quality and team efficiency. …/large-sized projects, particularly in single-page applications (SPA) or back-office systems. Experience in optimizing the performance of web applications. Strong knowledge of software engineering principles and design patterns. Understanding of backend technologies, including Node.js, Express, or similar frameworks. 5+ years preferred. Experience with RESTful API design and development. Familiarity with database management systems such More ❯

and manufacturing across advanced industries. By enabling high-fidelity, multi-physics simulation through AI inference across the entire engineering lifecycle, PhysicsX unlocks new levels of optimization and automation in design, manufacturing, and operations - empowering engineers to push the boundaries of possibility. Our customers include leading innovators in Aerospace & Defense, Materials, Energy, Semiconductors, and Automotive. Note: We are currently recruiting … career goals. What you will do Work closely with our simulation engineers, data scientists and customers to develop an understanding of the physics and engineering challenges we are solving Design, build and test data pipelines for machine learning that are reliable, scalable and easily deployable Explore and manipulate 3D point cloud & mesh data Own the delivery of technical workstreams … Create analytics environments and resources in the cloud or on premise, spanning data engineering and science Identify the best libraries, frameworks and tools for a given task, make product design decisions to set us up for success Work at the intersection of data science and software engineering to translate the results of our R&D and projects into re More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High-Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Opportunity: We’re partnering with a rapidly scaling AI infrastructure company, building the backend systems that power complex data pipelines and real-time APIs for global clients. You’ll work on the … platform - engineering high-performance Python services with FastAPI, integrating deeply with Kubernetes-native infrastructure, and deploying at scale in AWS. This is a backend-first role where you’ll design robust APIs, optimise cloud workloads, and ensure the platform runs reliably under heavy load. What You’ll Be Doing for this Backend Engineer, Contractor | Python, FastAPI, Kubernetes, AWS | High … Throughput Data & API Platform, Scale-up | £575-725/day Outside IR35 | 6 Months+ | Hybrid, London or UK Remote Designing and building internal & public APIs in Python (FastAPI) for high-throughput environments Architecting services with reliability and scalability as core principles Deploying containerised workloads in AWS via Kubernetes and Terraform Collaborating closely with DevOps, ML, and product teams to More ❯

have the opportunity to work across a modern engineering environment, collaborate with agile product teams, and contribute to a high-traffic platform used by millions of customers. Key Responsibilities: Design, build, and maintain scalable, high-performance services using Kotlin Provide technical leadership and mentoring to other engineers in the team Contribute to solution architecture and strategic technical direction Build … cloud technologies Key Skills & Experience 5+ years of back-end development experience using Kotlin Expertise in microservice architectures and frameworks like Spring Boot or http4k Deep understanding of RESTful API design and integration Proven experience mentoring engineers and contributing to high-performing teams Familiarity with Agile (Scrum or Kanban), TDD, and pair programming practices Experience with CI/ More ❯