Founding Engineer

Lemma offers an AI platform that automates prompt optimization and continuous learning for model improvement.

Location: San Francisco, CA
Company size: 2–10
Posted: 3w ago
Via: Yc

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Job listing · Updated 21 AUG 2026

Founding Engineer

Lemma· San Francisco, CA, USView company profile

Job title: Founding Engineer
Job location: San Francisco, CA, US
Job listing URL: https://www.ycombinator.com/companies/uselemma/jobs/wrFU6bU-founding-engineer
Job description: Lemma reads all of your agent conversations, finds the failures nobody knew to look for, and opens the PR that fixes them. ### Why this role exists You'd be the first engineer here who isn't a founder or a contractor. That means there's no engineering culture waiting for you to join it. The testing standards, the on-call story, how we decide what ships on a Friday, all of that is currently whatever the two of us happened to do last month. You'd be setting it, and you'd be living with it longer than we will. There's also no work stream attached to this job. You go where the gap is. Some weeks that's detection quality, some weeks it's the ingest pipeline choking on a customer whose instrumentation is a mess, some weeks it's the review UI that decides whether someone trusts our PR enough to merge it. We hire this role because the constraint on a team this size is almost never a specialist. ### What you'll do * Ship across the whole loop: ingest, detection, patch generation, verification, the product people actually look at * Own the trust surface. Reproduction, guardrails, and the checks that keep a bad PR from ever reaching a customer's repo * Take a problem from a customer conversation to something shipped, without waiting for a spec * Talk to customers directly. You'll be in their Slack, reading their traces, hearing what broke before we do * Make calls that outlive you. Schema decisions, service boundaries, what we're willing to be slow about ### What we're looking for * 3+ years shipping production software, and a track record of shipping well outside whatever you'd call your specialty * Strong TypeScript. It's the whole codebase, frontend through the core service * Real comfort with data at volume. You've thought about cost per event, not just correctness * Strong product sense. You can take a rough problem and return something well considered without a Figma file waiting for you * You've built with agents and have opinions about why they fail * Bonus: you were the customer once. You ran agents in production and got burned We move fast on hiring. Target is an offer within two weeks of first contact. Onsite in San Francisco. We sponsor visas.

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