Full-Stack Product Engineer

🏁 Take a Seat on the Pit Wall at Keystone AI, we aren't building another AI analytics dashboard. We're changing how sim racers and real drivers spend their off-track time. Mission: turn data into on-track speed.We want an engineer who owns a product, not closes tickets. Our stack is modern TypeScript — a Next.js web app and a Bun/Hono API powering AI coaching — with telemetry from Le Mans Ultimate, iRacing, and Assetto Corsa Competizione. The core pipeline and native recorder are built. The next chapter — making PitGPT actually read the data like a race engineer — is yours. See what we've built — no signup: https://app.racemake.com/share/drive/7XapDc3M 🎯 Your Mission You live across the whole product: the web app, the API, and the analytical engine that turns raw telemetry into insight. Build the analytical engine — the hard, interesting part. Today the product shows telemetry; next it has to understand it: cut a track into corners, split each into entry/apex/exit, read where the driver loses time and why. From the geometry of the lap, not guesswork. The brain of PitGPT, and you own it. Ship the product drivers use. Lap analysis views in React, charts, replay, dashboards. You build and tune them — fast rendering, clean UX. Make the AI trustworthy. You tune the prompts and tool-use so PitGPT coaches corner-by-corner for GT3 and LMdh cars — and never invents a corner that wasn't there. Every word traces to a real number. Stopping it hallucinating is the actual engineering. When a sim update breaks a telemetry format overnight, you ship the fix before users notice. Something breaks in prod, you fix it — not thread about it. 🛠️ Tech Stack & Skills A strong mid-level or senior engineer who can own the stack and ship from day one. TypeScript / React / Next.js — you move between UI and API without switching gears, and you're fast. Bun, Hono, ClickHouse, Protobuf, Zod — our backend isn't Express + Postgres. You pick up unfamiliar tools and read code you didn't write. A feel for data and math — noisy sensor streams into something a driver can act on: curvature, deltas, degradation. AI-native — Cursor, Claude, Copilot. You move fast with AI and catch it when it's wrong. Rust (a plus, not required) — our recorder is Rust + Tauri. Reading and extending it with AI makes you stand out. 🚀 What We Offer A startup going from virtual tracks to real ones. We're demanding, we push for results and clear communication, we want ownership. In return: Real ownership. No tickets handed to you. You own the technical direction and ship it. The first engineer here, done right, doesn't stay just an engineer. Access to motorsport. Chances to join tests and real races. Equity for the right person. Milestone-based, earned through impact — real upside as we grow. Contract or full-time. €40–60/hr (€320–480/day), or full-time around €5–6k/month. Depends on your seniority. We pay for speed and autonomy. Remote-first. Your home office, or ours in Prague. 🎮 The Engineering Challenge: Choose Your Pace CVs are cool, but show us you can ship. We don't review applications without a completed challenge. 🏁 BASIC — https://gist.github.com/743milan/91453ae11cffa9165f92cd7c650dbac5 🏆 HARD — https://gist.github.com/743milan/bf57fa0020b19efacf4d845590291a17 The basic one tells us you can ship. The hard one is where we find out how you think — a real problem we solve every day. The brief is the floor, not the ceiling; what you do past it is how we tell a strong engineer from a great one. We won't tell you what that is. Do one. Do both. The more we see, the faster we move. Include your code + output in your reply. If we see the signal, we’ll be in touch within 48 hours.