Blacksmith Hits $1B With $66M Series C Led by Sequoia as AI-Written Code Flood Tests Its CI Platform

AI code-testing startup Blacksmith raised a $66M Series C led by Sequoia at a $1B valuation, roughly double its $550M August round. The CI platform now runs 90 million validation checks per week across 10,000+ companies including Granola, Handshake, Supabase and LangChain, up from 5 million checks weekly at the start of 2026.