Lead UI Developer role using TypeScript, React, RxJS, WebSockets/SSE, GraphQL, Protobuf, Flatbuffers, Jest/Vitest, React Testing Library, Playwright, and AG Grid. You will own the front-end architecture for a real-time Single Dealer Platform used by Sales, Trading, and institutional clients globally, building low-latency trading applications for market data, pricing, RFQ, and trade capture.

Develop backend services using Node.js, Python, Java, C#, PHP, and Ruby on Rails, with databases including MySQL,

You will build and evolve customer-facing interfaces for AI Virtual Agents using React, TypeScript, Next.js and Vite, and refactor the frontend into a scalable platform with a shared component library and design system. Unitary’s factory builds custom operations agents that complete complex workflows end-to-end in customer tools.

Samsara★3.6 (32)· London

Samsara interns work on the Connected Operations Cloud, building backend infrastructure in Golang, web clients with TypeScript/React and GraphQL, mobile with React Native, or embedded software for IoT devices. Projects involve scaling data ingestion, real-time data processing, and creating actionable insights for industries like transportation and agriculture.

Backend engineers use Python, Django, Django-REST-framework, GraphQL (Graphene), Celery, Postgres, and AWS (Packer, Consul, Terraform). They build and maintain the AI-driven energy management platform that powers utilities and optimises renewable generation. The global engineering team is around 1,400 people.

Java (JDK 11+), multithreading, SQL/NoSQL databases (Oracle, MySQL, PostgreSQL, MongoDB, Cassandra), message queuing (Kafka, Tibco, Solace), Linux, JVM, and TDD. This tech lead role builds high-performance FX risk calculation systems for Citi’s Markets technology team, which supports global trading and risk management.

Reward Gateway★4.4 (11)· London

Define and champion the architecture vision for the Engagement Business Unit, working with global architecture and engineering leaders. The role involves leading architecture governance, establishing reusable patterns, and driving the adoption of AI-enabled engineering practices across APIs, microservices, event-driven systems, and data streaming platforms like Kafka. You'll partner with product and engineering teams to deliver scalable cloud-native applications and improve CI/CD pipelines and software delivery practices.

Koinly★3.0 (1)· London

Work with React 19, TypeScript, TanStack (Router, Query, Table), Radix UI, Mantine, Tailwind CSS v4, Vite, Vitest, Storybook, Highcharts, Sentry, Bun, and RabbitMQ on a data platform that reconciles crypto transactions and tax obligations for Koinly’s web application, with a React Native mobile app joining scope later.

Senior WordPress Developer role: build bespoke WordPress sites and apps using PHP, MySQL, ACF, WooCommerce, Gutenberg, JavaScript (ES6+), SASS/SCSS, Git, Composer, npm, Vite, CI/CD. You’ll also drive AI-assisted development (RAG, MCP, Copilot) and mentor junior developers.

Spotify★4.1 (116)· London

You will work with React, TypeScript, Java, GraphQL, PostgreSQL, and Google Kubernetes Engine (GKE) to build end-to-end solutions. The team builds Groove, a platform that helps thousands of employees plan, coordinate, and deliver work across Spotify.

Design, configure, and develop HR web applications using React, Next.js, and the HRSD platform. Build reusable UI components, integrate with REST/GraphQL APIs, and participate in CI/CD processes alongside product managers, designers, and backend engineers.

You will work with Java, Spring Boot (Spring Batch, Spring Cloud), microservices, REST APIs, GraphQL, Azure Cosmos DB, and Confluent Kafka. The team builds AI-driven digital products and services that support employees and HR stakeholders.

SQL, MySQL, PostgreSQL, Doris Event, QuickSight, and possibly Amplitude, Mixpanel, GA4, Airbridge, Adjust, Airflow, dbt, Git or Python. You will own analytics schema, data models, and BI dashboards for ZYMIX, a Gen Z social super-app launching in the UK, bridging product analytics with data building.

Working with Python, SQL, AWS, and APIs like GraphQL, gRPC, and REST, you will productise ML models and manage data workflows in cloud infrastructure. The HealthTech team focuses on ethical AI to improve patient care outcomes.

You will work with JavaScript, PHP, HTML, CSS, Laravel, Bootstrap, APIs/JSON/XML, MySQL, and optionally React. As part of a fullstack team, you will design, build, and maintain frontend and backend systems for a fine bridal jewellery manufacturer’s online platform, migrating legacy systems to Laravel.

MAREX★3.2 (6)· London

You will work with C# .NET, JavaScript, TypeScript, React, Node.js, GraphQL, Docker, NoSQL/RDMS databases, and AWS cloud services (ECS/EKS, Lambda, S3, RDS, API Gateway). The team builds and maintains applications to strengthen the company’s market-making capabilities and improve operational efficiency across multiple asset classes and geographies.

Cato Networks seeks a Senior Full Stack Engineer for their secured access team to design and build web security solutions and internal infrastructure platforms using Java, Go, Spring Boot, GraphQL, PostgreSQL, MySQL, MongoDB, and Redis. The role involves end-to-end development from large-scale data processing to web interfaces, working on enterprise SaaS microservices at scale across security products and infrastructure. Requires 6+ years backend development experience, SaaS microservices expertise, and familiarity with relational/non-relational databases in CI/CD environments.

Infosys★3.8 (17k)· London

You will work with Java, Spring Boot, Hibernate, JPA, React/Angular/Vue.js, HTML5, CSS3, JavaScript, RESTful APIs, SQL/NoSQL databases, Git, and CI/CD tools on cloud platforms (AWS, Azure, GCP). As a Senior Consultant at Infosys, a global digital services and consulting firm, you'll contribute across the consulting lifecycle—defining problems, proposing solutions, and guiding development, configuration, and deployment while mentoring teams and shaping client-focused solutions. Docker and Kubernetes experience is a plus.

Work with Golang, Kubernetes, gRPC, RESTful APIs, HashiCorp Vault, and cloud-native tooling to build AI-powered platforms. The team, part of Citi's Chief Technology Office, defines the bank's tech and engineering strategy by engineering cutting-edge products at planetary scale.

You will work with Node.js, React, JavaScript, TypeScript, REST APIs, MySQL, Git, Next.js, Express.js, and Tailwind CSS, along with AWS or GCP cloud infrastructure. Mas & Pas Limited is the employer; no specific product or project is described in this listing.

You will work with React, TypeScript, Next.js, Jest, Cypress, CSS-in-JS libraries, Git, and GraphQL. You will join the Customer Apps team to build and scale customer-facing applications for payment device management, loyalty schemes, and more at Dojo, the UK's largest payments acquirer.

Tripadvisor★3.9 (142)· London

You will work with Kotlin, Coroutines, Jetpack Compose, Cursor, GraphQL, and MVVM in a clean-architecture modular layout. You’ll join the Tripadvisor Experiences mobile team, focusing on Android app development with occasional backend microservices work.

Tripadvisor★3.9 (142)· London

Android Engineer role working with Kotlin, Coroutines, Jetpack Compose, Cursor, and GraphQL in a modular, clean-architecture MVVM layout. You will build and release code for the Tripadvisor Experiences mobile app, collaborating with product and designers on the full software lifecycle. This is a full-stack role where you primarily develop Android systems, with occasional back-end projects.

Senior Software Engineer designs and maintains backend services and APIs using Java, Python, and Node.js, working with microservices and Spring Boot. The role involves building REST, GraphQL, and SOAP APIs, using relational and NoSQL databases (MySQL, PostgreSQL, Oracle, Redis), and performing cloud-native development in AWS environments. This position supports financial systems and integrations within the leading global business aviation company, Vista.

Build and support scalable enterprise integrations using Workato, APIs, webhooks, REST, SOAP, GraphQL, OAuth, JSON, XML, SQL, JavaScript, Python, and Workato formulas. Integrations span finance, HR, CRM, document management, and analytics platforms. No team size specified.