Product Engineer (Mid-Level / Senior)

Sunsave | Product Engineer (Mid-Level / Senior) | London, United Kingdom (Holborn) | ONSITE (hybrid, 3 days/week in office) | Full-time Sunsave is building what replaces your energy supplier. Customers switch to solar and a battery with nothing to pay upfront: kit, install, finance and long-term protection in one package, and the battery trades energy on the grid every day to push their bills towards zero. Founded in 2022, £113m Series A (equity and debt) in 2025, more than 3x growth last year, nearly 90 people. I lead engineering and data science. Software runs every step of the customer journey: the quote, the finance application, the contract, the install and the battery trading. You'd join a small squad on one area: acquisition (website, quote, finance, contract), installation, in-life (customer app, monitoring, maintenance) or energy (battery optimisation and grid trading). Product engineers here own problems end to end, from working with the people who use what they build to running it in production. Agents do a lot of the implementation. We expect you to use them every day, delegate the implementation but never the thinking, and own every line you merge. We offer finance and hold customer data, so correctness, auditability and security matter a lot. Experience: 2+ years running production software for mid-level, 6+ for senior. TypeScript, NestJS, React/Next.js, PostgreSQL and AWS are a plus but not required. Right to work in the UK required. The interview is built for how we work. No leetcode. A ~45 min async review of a pull request written with AI, then a ~90 min live session where you shape and build a small problem close to our work with your own AI tools. JD: https://sunsave.notion.site/Sunsave-Product-Engineer-410e7b6... Apply: https://ats.welcometothejungle.com/board/sunsave-RTBuAt/job/...