Citi★3.9 (21k)· London

You will work with TypeScript, React, HTML5, CSS, JavaScript (ES6+), Chromium/Electron/OpenFin, FDC3, REST/WebSocket APIs, Kafka/Solace/Tibco, and CI/CD with Jenkins. The team delivers pricing solutions and trading GUIs for Citi’s Foreign Exchange business. You will provide technical leadership, mentor junior engineers, and drive AI integration.

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.

You will build scalable server-side logic using JavaScript, TypeScript, and Node.js in a microservices architecture on AWS with Kubernetes, Terraform, Kafka, and Snowflake. You will join the MMH team within the Martech domain, which orchestrates campaign delivery across email, push notifications, and personalised content for all Sainsbury’s Group brands. The team includes 7 engineers.

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

You will work with JavaScript (TypeScript), React, Redux, RX JS, NPM/Yarn, webpack, CSS, HTML, Azure DevOps CI/CD, and Java. As a senior developer on the FM Digital Channels team, you will build Blade, the bank's strategic in-house pricing, execution, and trade processing platform for Financial Markets.

Lead Python Developer role using Core Python, Flask, VueJS, JavaScript, CSS, HTML, SQL, AWS, Terraform, Docker, and serverless components, with CI/CD and Agile practices. The developer builds, enhances, and supports production applications within UK public sector programmes, collaborating with delivery, product, and data teams.

BNY★3.5 (5.5k)· London

You'll use Java 17/21 with Spring, Maven, Groovy, JavaScript/TypeScript (Angular), Docker, GitLab CI/CD, IntelliJ, Windsurf, Splunk, and AppDynamics to build secure backend services, batches, and APIs for a global financial services company.

Lovable★4.0 (43)· London

Uses Go, Rust, TypeScript; AWS, Azure, Google Cloud, Cloudflare; Kubernetes, Terraform, Temporal, OTEL, CI/CD; PostgreSQL, ClickHouse, Firestore, Spanner, BigQuery. Builds the platform for Lovable Enterprise enabling secure, cloud-agnostic deployment, defining architecture for sandboxing, networking, encryption, identity, and mentoring engineers.

Native Kotlin and Jetpack Compose development on a consumer-facing Android app for in-store grocery trips, running on a known device inside live stores. Integrates on-device edge AI (ML Kit, TensorFlow Lite) and uses AI coding tools like Cursor or Claude Code. Reports to the Head of Android.

Work with Java, Python, JavaScript/TypeScript, Go, cloud platforms (AWS, Azure, GCP), CI/CD pipelines, and version control. Guiding the technical direction of BabuSpace’s premium short-term rental marketplace platform for African cities, designing backend architectures, and mentoring engineers.

Build enterprise-grade web applications using Python (Django/FastAPI), React, TypeScript, and PostgreSQL. Develop RESTful APIs, responsive UI components, and contribute to system design, CI/CD pipelines, and performance optimization.

You’ll work with Python (Django/FastAPI), React, TypeScript, PostgreSQL, REST APIs, and CI/CD. You’ll own end-to-end feature delivery on scalable, enterprise-grade web applications.

Build high-performance front ends with React, TypeScript, JavaScript, React Hooks, and ES6/ES7 for a leading HFT firm in London. The role focuses on UI engineering within a trading environment.

Java and Spring Boot, React, AWS, and CI/CD pipelines are the primary technologies. You will build microservices-based customer-facing applications for a leading retail bank’s cloud-native digital banking platform. No team size is stated.

Deloitte★3.9 (14k)· London

You will use Figma, React, TypeScript, and HTML/CSS to design and front-end code AI-powered agentic experiences, including conversational interfaces and agent-orchestration workflows for clients. The team reimagines how users interact with intelligent platforms, developing trust-centered, multi-step AI interactions. You will manage design workstreams and mentor junior designers and front-end developers.

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.

Koinly★3.0 (1)· London

You will work with TypeScript on Bun, RabbitMQ, Redis, PostgreSQL, Vitest, Sentry, and Rust. The team owns the distributed data-processing backend that ingests, normalizes, and reconciles on-chain and exchange data for Koinly’s crypto tax calculation product.

Build Android fitness app features with React Native and Expo, using Claude for AI-assisted development and agentic workflows. 1-month contract fully remote.

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.

Build and maintain the company’s platforms using JavaScript, Node.js, Next.js, Express.js, React/React Native, .Net 4.8/9/10, C#, HTML/CSS, and API Restful Services. You will develop both web and mobile applications, collaborating with the team while working independently.

DeepL★3.8 (4)· London

You will work with C#, Python, and JavaScript to build full-stack features on the Media Translation team, which develops DeepL’s core translation products—including the consumer web translator, Enterprise Customization Hub, and multimedia localization flows.

You'll work with Python and/or TypeScript, using full-stack JavaScript or backend Python. The role is a founding engineer at a stealth AI company backed by a £100M bootstrapped founder with three successful exits.

Palantir★3.9 (37)· London

As an intern at Palantir, you will write high-quality code for Palantir Gotham, Foundry, or Apollo using Java, Go, and TypeScript, along with open-source tools like Cassandra, Spark, Elasticsearch, React, and Redux. You will join a small product-development team building features for users in public and private sectors, such as research scientists and intelligence analysts.

Palantir★3.9 (37)· London

You’ll work with Java, C++, Python, TypeScript, JavaScript, Kubernetes, Cassandra, Chromium, and open-source tools. As a new-grad infrastructure engineer, you’ll contribute to the shared infrastructure behind Palantir Foundry, Gotham, and Apollo—platforms deployed at key public- and private-sector institutions—as well as to Rubix and Mission Manager for sensitive environments. Teams are small, focused on backend, developer, frontend, or storage infrastructure, or on production infrastructure including a Kubernetes-based PaaS, Apollo, and Signals.

Palantir★3.9 (37)· London

You'll use Java, Go, and TypeScript alongside open-source tools like Cassandra, Spark, Elasticsearch, React, and Redux with Gradle and GitHub. You'll contribute to Palantir Gotham, Apollo, or Foundry—data platforms deployed across critical institutions.