He sold his $10M business to bet on a side app—then grew it to $20M ARR. | Andrew Antos, Co-Founder & CEO of Within

Andrew spent two and a half years selling AI contract review to lawyers. It stalled at $800K. He rebuilt the company around finance teams and grew that to $10M. Then he demoed a little internal tool on the side at his own conference, and nobody wanted to talk about anything else. It did $350K in five weeks. He sold the $10M business and went all in on the side tool—Within went from zero to nearly $20M in 18 months.

In this episode, Andrew breaks down the 30-and-100 rule he uses to validate every idea, how he turned every customer conversation into a database that tells him what to build next, and why nine out of ten experiments have to fail.

Why You Should Listen

• Why 30 conversations validate an idea and 100 customers reveal product market fit.
• Why the thing everyone asks about matters more than the thing you launched.
• How to tell that slow growth is a market problem, not a go-to-market problem.
• How to run four bets a quarter with a kill metric on every one.

Keywords startup podcast, startup podcast for founders, product market fit, finding pmf, Within, Klarity, Andrew Antos, enterprise AI, AI transformation, pivoting a startup, enterprise sales, legal tech, finance automation, AI agents, customer discovery, voice of customer

Chapters

• 00:00:00 Intro
• 00:02:04 The Side Tool Everyone Wanted
• 00:04:26 $350K in Five Weeks
• 00:05:42 AI for Lawyers Before AI Worked
• 00:12:44 Stuck at $800K
• 00:13:43 Choosing Finance Over Legal
• 00:17:40 The 30 and 100 Rule
• 00:24:59 Selling the $10M Business
• 00:32:17 Building a Company Data Brain
• 00:40:01 Nine of Ten Bets Fail