Blacksmith Series C values code-testing startup at $1 billion

The Blacksmith Series C shows where money is flowing in AI coding. Blacksmith, which runs continuous integration, the automated building and testing of code before it is merged, raised $66 million in a round led by Sequoia Capital that values it at $1 billion, it said on Wednesday, Oct. 21. Premji Invest joined, as did earlier backers Peak XV Partners, GV and Y Combinator.

What happened

The round brings total funding to $125 million. It came two months after a $45 million Series B at a $550 million valuation, and a year after a $10 million Series A at $60 million, TechCrunch reported.

Growth has been steep. Weekly CI jobs on the platform climbed from 5 million in January to over 90 million, while annual recurring revenue rose 17-fold over the same period, the company said. More than 10,000 companies use it, including Mercury, Granola, Handshake and LangChain. Customers see jobs finish twice as fast at 60% lower cost on average, Blacksmith claims.

The company runs just under 10 megawatts of computing capacity in U.S. and European data centers and aims to grow that fivefold in 2027. The new money will go to hiring and compute.

Why it matters

The pitch is simple: AI agents now write code faster than teams can check it. Blacksmith cited Anthropic, which reported that its CI job volume grew 25 times in six months after Claude began writing most of its code. "As agents write more of the world's software, the question that matters is whether it can be trusted," chief executive Aditya Jayaprakash wrote.

CI is also an awkward workload for general-purpose clouds. One customer's demand can spike from nothing to tens of thousands of processors and fall back again, and Blacksmith says it built its stack to absorb those spikes. Sequoia partner Isaiah Boone credited the team's systems expertise and speed.

The Blacksmith Series C fits a wider pattern of investors backing tools around AI models rather than models alone, alongside deals such as Arena's $3.1 billion valuation and Legora's legal AI round.

What's next

Jayaprakash, Aayush Shah and Aditya Maru, who met as Waterloo undergraduates, started the company in 2024; its team is split between New York and San Francisco. The founders explain the plan in the Series C announcement.

Jayaprakash said nearly every large engineering team now opens with the same problem. "Developers who used to push three or four pull requests a day are now pushing orders of magnitude more and their CI infrastructure can't keep up," he said in the release. Before that, Shah and Maru were among Cockroach Labs' first engineers and Jayaprakash was at Faire. Switching takes a single-line edit to a workflow file, the company says.

Competition will come from the big clouds and code hosts that run their own CI. The test for the Blacksmith Series C valuation is whether agent-driven code volume keeps rising if the AI spending boom cools.