Senior Frontend Engineer

About Heidi SystemsHeidi Systems builds the energy OS for real estate. We help property managers and owners get their heating, water and electricity meters online, see consumption in real time and run the yearly utility billing without paper, Excel and site visits.Submetering in Germany is still mostly analog. Meters get read by hand, data sits in PDFs, and tenants see their consumption once a year. We change that end to end: we install the meters and gateways in the building, collect the data and build the web platform property managers work in.We're a small team in Berlin. Product and engineering work directly with the founders, and what you ship lands with real customers fast.The roleWe're looking for a best-in-class frontend engineer. Someone whose code other engineers learn from.You'll be our senior frontend engineer and own the web platform end to end: architecture, code quality and the day-to-day experience of the property managers using it.The platform is a SvelteKit and TypeScript app. It shows consumption data per building and unit, flags anomalies, manages tenants and owners, and produces the documents for the yearly billing. A lot of it is data-heavy UI, and it has to be right, because the numbers end up on invoices.You'll work closely with our backend engineers and the founders, and you'll help onboard and mentor junior developers and interns as the team grows.What you'll doOwn the frontend architecture of our SvelteKit app: routing, load functions, SSR, state and how we talk to the backend via oRPCShip features end to end, from a rough idea with the founders to production, often before the design is finalBuild the data-heavy parts of the product: consumption dashboards, notification rules, tenant and owner management, billing documentsSet up and maintain our component library on Tailwind and DaisyUI so the UI stays consistent as we add featuresRaise the bar on quality: strict TypeScript, Vitest coverage, code reviews, a sane PR flowShape the API contract together with backend (types, Zod schemas, error handling) so frontend and backend stay in syncMentor juniors and interns through reviews and pairingWhat you bring5+ years of professional frontend experience, ideally at startups or other fast-moving product teams2+ years building production apps with Svelte and SvelteKit, with a deep understanding of its reactivity model, stores, lifecycle, routing, load functions and SSRStrong TypeScript: strict mode, generics, utility types, and the judgment to know when types help and when they get in the wayHands-on with Tailwind CSS (DaisyUI is a plus)Experience with RPC-style APIs (oRPC, tRPC or similar) and typed contracts between frontend and backendTesting as a habit: Vitest, JSDom or comparable toolingComfortable in a Unix environment (Linux or macOS), with Git, branches and PRsYou've made architecture decisions on a real product and can explain the trade-offsYou work well with little oversight and ship in small, frequent stepsFluent English, written and spokenYou're in Berlin or willing to move, and you're in our office 2 to 3 days a weekHow we workHybrid in Berlin. You're in the office 2 to 3 days a week. That's fixed. The rest of the week you work from wherever you like.Short paths. You talk to the founders directly, most decisions take one call.Real ownership. The frontend is yours to shape, and you'll set many of the standards the team builds on.Real impact. Your work runs in buildings across Germany and makes energy use visible where people live.Room to grow with the company as the engineering team gets bigger.Your next stepsIf you match most of these requirements and are ready to help digitize the building sector, we encourage you to apply. You will join a growing team where your work directly shapes the future of energy management in real estate.Find more English Speaking Jobs in Germany on Arbeitnow