> Markdown version of [/jobs/ext/2992509-frontend-engineer](https://www.wearedevelopers.com/jobs/ext/2992509-frontend-engineer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Frontend Engineer - **Company:** HASH - **Location:** London, UK - **Experience:** Expert - **Salary:** £70,000.0 - £120,000.0 - **Contract:** Permanent contract - **Skills:** HTML, Artificial Intelligence, Business Process Model and Notation, Software Quality, Collaborative Software, Software Debugging, Open Source Technology, Software Product Management, Real Time Simulation, Software Requirements Analysis, TypeScript, UML, Management of Software Versions, Web Content Accessibility Guidelines, Web Applications, WebGL, ReactJS, Backend, Data Analytics, Front End Software Development, Restful APIs - **Published:** September 19, 2026 - **Apply:** https://www.adzuna.co.uk/jobs/details/5889011371 ## About the Role * Expertise with React, TypeScript, modern HTML & CSS * Proven track record architecting and delivering rich web apps that involve complex user interactions * Rigorous approach to documenting and versioning components for external audiences * Experience profiling and debugging performance in devtools * Comfortable taking a visible technical leadership role, mediating discussions around standards and implementation approaches, and taking accountability for the delivery of features on time and to spec * Excellent written & verbal communication in English and comfort working async * Familiarity with process/model-oriented UIs: BPMN, UML, systems-dynamics models, graphs, etc. * Understanding of WCAG 2.2 and pragmatic accessibility techniques (ARIA, focus management, keyboard UX) * Public record of maintaining a well-documented, semantically versioned library (ideally in an open-source context) * Experience with CRDTs or other real-time collaboration solutions * Hands-on experience with WebAssembly pipelines * Canvas/WebGL experience for high-performance rendering ## Description We're a fast-growing deep-tech company crafting web-based tools that help people model, understand, and optimize real-world systems and processes using AI. From interactive process-model editors to real-time simulations, we turn complex, non-textual data into intuitive, responsive, accessible web apps designed to be used by non-technical domain experts at research labs, startups and enterprises worldwide. As a senior Frontend Engineer you'll own end-to-end delivery of novel world modeling and AI native interface components, helping shape our frontend architecture, as part of an Advanced Research + Invention Agency funded project building systems for delivering "Safeguarded AI". You'll collaborate with technical product management, UX researchers and AI engineers from top labs, as well as our own developers and leadership, to push the boundaries of what a browser can do - whether that's a drag-and-drop model builder, timeline-based simulator, or multimodal feedback interface. What you'll work on Day to day, you'll: * Design, build, and ship production-ready React/TypeScript components and app-wide features for complex data-driven UIs * Work with mathematical experts to convert world-modeling theory formalizations into software requirements, and writing tests which ensure implementation correctness * Convert novel UX/UI designs - for new world modeling and AI-interaction features - into performant, responsive and accessible experiences that work across devices * Establish project-wide standards for code quality (e.g. via linting), review and testing, and provide feedback on the work of other frontend engineers * Profile and optimize rendering performance for complex interactions and visualisations * Tell the story of best practices and lessons learned in developing and testing novel, complex world-modeling interfaces, e.g. via blog posts and workshops * Partner with backend/infra teams to identify and manage interdependencies, and to help define robust APIs that support excellent, feature-rich frontend performance * Stay on top of emerging browser capabilities and drive adoption of the ones that matter ## Related Videos - [Rendering Design Software in the Browser at Penpot](https://www.wearedevelopers.com/videos/1353-rendering-design-software-in-the-browser-at-penpot) - [ChatGPT and Java: A Match Made in Heaven or Hell?](https://www.wearedevelopers.com/videos/536-chatgpt-and-java-a-match-made-in-heaven-or-hell) - [The Resilience of the World Wide Web](https://www.wearedevelopers.com/videos/1281-the-resilience-of-the-world-wide-web) - [But, you're not Facebook](https://www.wearedevelopers.com/videos/378-but-you-re-not-facebook) - [WeAreDevelopers LIVE – From JavaScript to WebAssembly, High-Performance Charting and More](https://www.wearedevelopers.com/videos/1794-wearedevelopers-live-from-javascript-to-webassembly-high-performance-charting-and-more) - [WeAreDevelopers LIVE - Streaming HTML](https://www.wearedevelopers.com/videos/2135-wearedevelopers-live-streaming-html) ## Related Articles - [Dev Digest 133 - Back to Front](https://www.wearedevelopers.com/magazine/474-dev-digest-133-back-to-front) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline) - [Dev Digest 113 - Debugging above the cloud](https://www.wearedevelopers.com/magazine/422-dev-digest-113-debugging-above-the-cloud) - [Dev Digest 139 - Soft and hard queries](https://www.wearedevelopers.com/magazine/487-dev-digest-139-soft-and-hard-queries) - [Dev Digest 131 - AI'm not sure about OSS](https://www.wearedevelopers.com/magazine/472-dev-digest-131-ai-m-not-sure-about-oss)