Lemma is a YC F25 company building production monitoring for AI agents. We help companies automatically improve their AI agents from production data by catching the silent failures your observability tools miss and building self-healing loops.
We're backed by Y Combinator, Matrix, Liquid 2 and operators from OpenAI, xAI, and Doordash. We look for people who act like founders - driven by the mission, biased toward action, and committed to craft.
Our product's job is to make an engineer trust a fix they didn't write.
That's a design problem more than a technical one. Someone has to look at a surfaced failure and understand in about four seconds what broke, how often, who it hit, and whether our proposed patch is right. If that takes forty seconds instead, they close the tab and go back to grepping logs.
So the surface area here is dense and unglamorous. Trace timelines, diff views, evidence chains, nested detail states, tables that have to stay readable at ten thousand rows. This is not a marketing site job. If you want to make beautiful things, there are easier products to make beautiful.
You'd be the first designer here, which means you're setting the system, not applying one.
- Own the product surface end to end: detection review, trace exploration, the PR review flow that decides whether we get trusted
- Build the design system from nothing, and keep it alive as the product changes under it weekly
- Ship your own work. You'll be in the codebase, not handing off Figma files
- Sit in on customer calls and watch real engineers use this. The gap between what they say and what they do is where the work is
- Make the hard call about what not to show. Most of this product is about hiding 99% of the data well
- 3+ years designing software, with real examples of complex, data-dense interfaces. Consumer polish alone won't transfer here
- You write code. React and TypeScript, well enough to ship your own work to production
- You've designed for engineers before, or you are one. Knowing what a trace is and why a diff view is hard saves us months
- Taste you can defend. We'd rather hear why you cut something than why you added it
- Comfortable with ambiguity. Nobody here will hand you a spec, and the product changes weekly
We move fast on hiring. Target is an offer within two weeks of first contact.
Onsite in San Francisco. We sponsor visas.