YC's codebase hits 4M lines, adding 2M and 350+ internal AI tools since March

garrytan · x · 2026-08-20

Y Combinator partner Garry Tan revealed the evolution of the company's internal codebase, growing from a 2013 "Bookface" to 4 million lines running on a single PostgreSQL. It supports applications, interviews, co-founder matching, and more. Notably, 2 million lines and over 350 internal AI tools were added since March. Tan suggests that while YC isn't a software company, this level of internal software development is the direction all companies are heading.

Original post →

More from coding & agent

coding & agent channel →