Blacksmith has raised $66 million in Series C funding at a $1 billion valuation as the infrastructure company scales its platform for building and testing software amid rapidly increasing code generation from AI coding agents. The round was led by Sequoia Capital, with participation from Premji Invest and existing investors Peak XV Partners, GV, and Y Combinator. The financing brings Blacksmith’s total funding to $125 million and will support expansion of its team and computing infrastructure.