Design Engineer

About this role

Mercura ( YC W25 ) helps the companies that build the real world move at software speed, automating the back-office work that runs the $12 trillion industry behind every hospital, school, and power plant. We started with one of their biggest bottlenecks - turning messy technical requests into accurate quotes - and eightfolded our revenue in 12 months . With a team of 16, we're now targeting $10M by the end of 2026 as well as our expansion into the US.

About the role You are the second designer here, and you own product surface end to end: you find the problem, decide if it's worth solving, design it, build it, ship it, and then check whether it worked. That last part is the job. Most designers stop at handoff. You won't have one. You'll sit with a German construction supplier watching them fight a spreadsheet, decide which of their five complaints is the real one, and have something in front of them within days.

Then you'll open PostHog to find out if it moved anything. We ship fast and polished. If those feel like you, this is the right role for you. What you will be working on Find the real problem. Run your own customer conversations — no PM filter. Distinguish what users ask for from what they need, and be willing to conclude something isn't worth building. Ship it yourself. Design and write the production code. React/TypeScript.

You own the result, not a layer of it. Know if it worked. Instrument what you ship. Define the success metric before you build. Kill your own features when the data says so. Set the quality floor. Empty states, loading states, error states, keyboard behaviour, the transition that makes a slow thing feel fast. Nobody is going to catch these for you. Compress the loop. Prototype in whatever gets to a real answer fastest.

Speed here means speed to validated user value, not speed to merged PR. What we're looking for Evidence of discovery. You've changed your own mind about what to build because of something a user said or did. You can tell us about a time you were wrong. Evidence of analytics. You've made a product decision from data you instrumented yourself. You know the difference between a metric that moved and a metric that mattered.