Lemma YC Application

Fall 2025Active

Lemma went through Y Combinator in the Fall 2025 batch as a B2B company. Below: what the company does, who founded it, and its application to YC, reconstructed question by question in the real YC form.

YC batch: Fall 2025
Industry: B2BEngineering, Product and Design
Team size: 2
Status: Active
Launched: 2025

Founders

Jerry ZhangFounder
Cole GawinFounder

What Lemma does

Lemma catches the silent, semantic failures your observability tools miss, where your AI agent looks like it worked but didn’t. We scan every trace to surface issues before users complain, identify root causes, and help you fix them without manual digging, so your agents improve over time.

Lemma's YC application, reconstructed

Y Combinator application

Lemma, Fall 2025 batch. The real form questions, answered from public data.

Founders2
Company7
Progress7
Idea4
Equity3
Curious2
Batch Preference1

Company

Company name

Lemma

Describe what your company does in 50 characters or less.

Reliability platform for AI agents

What is your company going to make? Please describe your product and what it does or will do.

We built a platform that detects semantic failures in AI agents that traditional observability misses. Lemma scans every trace to show when an AI looks like it succeeded but actually didn't, pinpoints root causes, and helps teams fix those errors without manual investigation.

Where do you live now, and where would the company be based after YC?

We live in San Francisco, CA, and Lemma will remain based here after YC.

Explain your decision regarding location.

San Francisco is where we built our network and are closest to early users building AI agents. Staying here lets us move faster and tap into the local ecosystem we know.

21 more answers in the full application

Founders, Progress, Idea, Equity, Curious, Batch Preference are in the full version. Create a free account to open it in YC Insights, next to every other YC batch.

See full application

Frequently Asked Questions

Is this the real Lemma YC application?

No. Y Combinator keeps submitted applications private. This is a reconstruction: the real YC form questions, answered from Lemma's public data (launch notes, founder backgrounds, product description). It shows how a company like Lemma would present itself to YC, not the text they submitted.