Poolside AI just closed a $500M Series B at $3B valuation — here's how two ex-GitHub executives built a coding assistant that rivals Copilot.

What it is: AI coding platform with domain-specific models trained on 500K+ open-source repos using their proprietary RLCEF method.

How it happened:
• Warner (ex-GitHub CTO) met Kant in 2017 during failed acquisition talks
• Spent 6 years plotting AI-driven developer tools while Warner was at Redpoint VC
• Founded in May 2023 with $126M seed at $526M valuation
• Hired ex-GitHub CRO Paul St. John for enterprise go-to-market
• Secured AWS partnership for Bedrock deployment
• Raised $500M Series B led by Bain Capital in 18 months

Key insight: Domain expertise + enterprise relationships + technical differentiation = massive valuation jumps.

Source: Contrary Research

Brewed by Startup Beaker.