Frontend Software Engineer

📣 Frontend Software Engineer — Climate Tech Nonprofit 💰 £62k–£77k per year 📍 London Hybrid — 2 days in London / 3 remote 💻 TypeScript · React · TanStack · Data Visualisation · Tailwind 🌍 Climate impact · Energy-system modelling · Open-source technology I’m working with a climate-tech nonprofit building software that helps governments, policymakers and energy planners make better decisions about the transition to cleaner electricity systems. This isn’t a standard frontend CRUD role. The team is building Scenario Builder — a browser-based platform used for energy-system modelling, grid planning, decarbonisation analysis and long-term infrastructure decisions. The frontend engineering problems are genuinely interesting. You’ll be building spreadsheet-like interfaces, interactive visualisations, filtering workflows and complex data-heavy features over datasets that can run into millions of rows — including input tables of around 5.1 million rows, well beyond what Excel can handle. They’re now looking for a Frontend Software Engineer to join a small interface team working on a modern, greenfield React and TypeScript codebase. You’ll work closely with a Principal Frontend Engineer, Product, UX, backend engineers, AI engineers and energy specialists, with plenty of ownership over the features you build. The work can vary significantly sprint to sprint — from large data grids and visualisation to AI-powered product features. Could be a strong fit if you: • Have 3+ years building production frontend applications with React and TypeScript • Have built complex, data-heavy interfaces involving tables, filtering, forms or visualisations • Understand frontend performance and how to work efficiently with large datasets • Have experience with client-side caching, synchronisation and invalidation — TanStack Query or similar • Have worked with frontend testing across unit, component, integration or E2E levels • Enjoy building reusable, accessible components and modern frontend architecture • Are comfortable working closely with Product, UX and backend teams • Enjoy solving difficult frontend problems rather than simply implementing standard screens Experience with AG Grid, D3, AG Charts, TanStack Table/Virtual or Parquet would be particularly useful, but isn’t essential. Climate or energy experience isn’t required either — they’re much more interested in strong frontend fundamentals and people who enjoy technically challenging product engineering. This is a good opportunity for someone who wants meaningful ownership, technically difficult frontend work and the chance to build software that has an impact beyond commercial optimisation. Apply to learn more.