The $1B Company Fixing AI’s Software Bottleneck

Blacksmith (YC W24) is building a faster cloud for continuous integration (CI), helping developers test and ship code as AI coding tools generate more of it. As software production accelerates, testing and validation are becoming the new bottleneck. That shift has helped Blacksmith grow 20x over the last year, and the company recently raised a $66 million Series C at a $1 billion valuation. The founders started as outsiders to DevOps and built their first infrastructure using the same high-performance CPUs found in gaming PCs, renting servers originally designed for Minecraft and Call of Duty. Today, they run a much larger fleet with a team of just 30 people, helping companies cut CI waits from minutes to seconds. In this first episode of Built to a Billion, they share how they found the idea, won their first 200 customers, and why faster testing will become even more important as agents write more of the world’s code. https://blacksmith.sh Chapters: 00:00 — Making CI Faster With Gaming CPUs 03:46 — Winning Over Investors and Developers 06:46 — Scaling CI for the AI Coding Era Apply to Y Combinator: https://www.ycombinator.com/apply Work at a startup: https://www.ycombinator.com/jobs