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.

You will build production mobile apps for iOS and Android using React Native, TypeScript, and integrate AI, natural-language features, Swift, Kotlin, and Python. The venture-backed startup creates AI-powered software that replaces manual workflows for industrial and operational teams.

You will own an existing production React/TypeScript application across web, iOS, and Android, integrating with Python/FastAPI backends and managing CI/CD pipelines. The team builds a computer-vision platform that turns video data into actionable insights. You will drive frontend architecture on a small, collaborative engineering team.

Foundation Partners Group★2.6 (165)· London

Typescript, Python, full-stack web development, frontend focus, offline support, observability, and testing across devices. You will build and scale consumer-facing production web applications for Flok Health, an AI-native healthcare company transforming care for MSK pain.

Senior Software Engineer role at Everfox, working with modern C++ on cross-platform desktop (Linux, Windows) and mobile (Android, iOS) apps, plus Java/Kotlin, Swift/Objective-C, Qt, GitLab, Docker, Kubernetes, and Python. You will build and maintain the end-point software layer for the Hardsec product line’s secure browsing and VDI solution, owning design, development, and delivery. You will also coordinate a small team of engineers and manage release planning across multi-platform shipped products.

React, Node.js, AWS, TypeScript, React Native, RESTful and GraphQL APIs, serverless architectures, CI/CD, PostgreSQL, DynamoDB, and AI tools such as Claude and GitHub Copilot. Build and ship digital products for a pre-IPO challenger bank serving mass affluent clients, owning full-stack work from architecture to production monitoring.

Proton★5.0 (1)· London

You will work with Kotlin, Jetpack Compose, and an increasingly shared Rust core to build Android applications. You will join a product team working on Proton Drive, Payments, or Account, building privacy-first tools for millions of users.

Proton★5.0 (1)· London

You will work daily with C#, TypeScript, and Rust, also providing bindings for Swift and Kotlin, using tools like Grafana, Prometheus, Sentry, GitLab CI, and Playwright. The Drive Foundation team builds the SDK that powers Proton Drive, ensuring cross‑client consistency and serving as the backbone for the encrypted cloud storage service.

Smarkets★5.0 (2)· London

Build web and mobile apps with Next.js, React, React Native, TypeScript, Redux, React Query, WebSockets, and REST APIs, using Figma for design and GitLab with Kubernetes for DevOps. You will craft polished interfaces for Smarkets, which operates one of the world’s most sophisticated prediction markets for sports and political events.

Build full-stack mobile applications using React, Node.js, AWS, React Native, TypeScript, JavaScript, GraphQL APIs, serverless architectures, CI/CD, PostgreSQL, and DynamoDB. You'll design, develop, and ship digital products for Monument, a challenger bank serving the mass affluent, with ownership from architecture to production.

Rightmove★3.7 (31)· London

Java, Spring Boot, Elasticsearch, Kafka, Gradle, Hibernate, Couchbase, SQL, and Docker. You will build and improve microservices that power Rightmove’s iOS and Android apps, working in a cross-functional team.

Depop★4.4 (61)· London

This Senior Backend Engineer role uses Scala (primary), TypeScript, Python, Play Framework, Kubernetes, PostgreSQL, DynamoDB, and Kafka. The Shipping Experience team builds and evolves the end-to-end shipping journey for buyers and sellers on Depop’s peer-to-peer circular fashion marketplace.

Build production-grade cross-platform apps with React Native, TypeScript, and native modules (Swift/Kotlin). You'll design offline-first mobile workflows with AI integration (LLMs, agents) and build backend services (Python a plus). The team is removing manual barriers in industries like aerospace, healthcare, and energy.

Deliveroo★3.3 (1.5k)· London

Lead a full-stack team (~7–8 engineers) building the real-time, back-office workspace used by 30,000+ support agents across Deliveroo, DoorDash and Wolt. The stack includes Go, Python or Node.js (backend), React (frontend), with cloud tooling (Kubernetes, AWS, Datadog) and an in-house chat platform handling tens of millions of conversations monthly.

Deliveroo★3.3 (1.5k)· London

Work with R/Python, SQL, and Cursor/AI tools to design experiments including A/B tests and causal inference. As a Senior Data Scientist on Deliveroo’s three-sided marketplace, you drive high-quality decision-making across product, operations, and platform teams.

Works with SAST, DAST, SCA, Burp Suite, OWASP ZAP, Semgrep, Python, Java, Kotlin, Go, JavaScript, and CI/CD pipelines (GitHub Actions

Proton★5.0 (1)· London

Build the Proton Drive Linux client from scratch using GTK+ or Qt, with Rust as a nice-to-have, and manage Git, CI/CD pipelines, and Linux packaging for Debian and Fedora. The Proton Drive team provides secure cloud storage and collaborative editing, and this greenfield project will create the first native Linux client.

Proton★5.0 (1)· London

Join Proton's Inbox Desktop team to rebuild the Proton Mail Desktop App, Mail Bridge and Export tool using a cross-platform Rust stack. You'll work with Golang, C++, Qt, JS, TypeScript, React, Electron and standard dev tools (Git, GitLab CI, Jira). You’ll take technical ownership of the Windows and Linux desktop clients within a cross-functional team of about 60 engineers.

Proton★5.0 (1)· London

You will work on iOS apps using Swift, Xcode, and Apple platforms, with a growing Rust-based logical core. You'll join a product team building privacy-first tools for Proton’s encrypted email, VPN, cloud storage, and password management services used by millions.

Proton★5.0 (1)· London

As a Senior Front End Engineer on the Standard Notes team, you will work with JavaScript, TypeScript, React, ES6, Playwright, Jest, and Grafana. The team builds a secure note-taking and productivity platform, developing features like encrypted search and cross-platform sync using end-to-end encryption. All Standard Notes codebases are open source.

Proton★5.0 (1)· London

You will work with PHP/Symfony for backend services, React for frontend, Kotlin (Android) and Swift (iOS) for mobile, with a growing shared Rust codebase, on Kubernetes infrastructure. The Payments team builds and scales payment methods and client libraries to enable subscriptions across Proton’s encrypted email, VPN, Drive, Pass, and Calendar products. The team works closely with the Account and Finance teams and across all business units.

Proton★5.0 (1)· London

Engineering Directors at Proton set technical direction and work with PHP (Symfony), Rust, Python, Swift, Kotlin, Jetpack, Typescript, React, C#, SQL, Redis, MySQL, and Ceph across mobile, desktop, web, and backend platforms. They lead engineering for one of Proton’s existing or upcoming products—such as Proton Mail, VPN, Calendar, Drive, or Pass—which provide private, secure, open-source tools to over 100 million users. The role involves managing a team of managers and driving DevSecOps practices.

Funding Circle★3.5 (53)· London

You will work with React Native, React.js, TypeScript, Firebase, Gradle, XCode, REST APIs, and CI/CD for app releases on iOS and Android. The role involves building and scaling a mobile app for Funding Circle’s fintech platform that uses data to provide fast funding to small businesses.

Ebury★3.3 (13)· London

You will work with React Native, React, TypeScript, Python, PostgreSQL, Redis, Expo pipelines, AWS, and Git. You join Ebury’s Mobile Platform team to evolve the mobile app by building features, services, and frameworks that empower product teams to ship efficiently while maintaining a unified customer experience.

Depop★4.4 (61)· London

Depop seeks a Backend Software Engineer for its Search Retrieval team working with Python or Scala, AWS, and modern cloud infrastructure. You'll collaborate with product managers, data scientists, and mobile/web engineers to build search and information retrieval systems serving 1M+ daily active users on Depop's peer-to-peer secondhand fashion marketplace.