Blacksmith, a Y Combinator W24 company, has raised $66 million in Series C funding led by Sequoia at a $1 billion valuation. The startup builds faster cloud infrastructure for continuous integration—the process developers use to test and ship code—as AI coding tools generate increasing volumes of code.
Founded by three engineers new to CI pipelines, Blacksmith discovered an unconventional solution using gaming CPUs instead of traditional server hardware. The approach dramatically cut testing wait times: for LangChain, they reduced CI latency from 15–20 minutes to 10–15 seconds. The company has grown 20x over the past year with just 12 engineers.
Blacksmith frames code validation as the emerging bottleneck in software development as AI coding accelerates. The team is planning autonomous QA tools that provide developers with evidence their changes work correctly.
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