Blacksmith hits $1 billion valuation with $66M Series C round

Blacksmith Software Inc. is now worth $1 billion after closing a $66 million Series C round led by Sequoia Capital. The round, announced today, also drew participation from Peak XV Partners, Y Combinator and GV, and lifts the continuous integration startup's total funding to $125 million.

The pace of the raise is the story inside the story. Blacksmith raised $45 million in a Series B led by Peak XV just two months ago, and before that it raised $10 million in September 2025. A company founded in 2024 has now compressed three rounds, and unicorn status, into roughly a year.

What does Blacksmith actually sell?

The startup, led by co-founder and Chief Executive Aditya Jayaprakash, offers what it calls a "CI cloud" — a dedicated service for continuous integration, the process of building and testing new code before it is merged into a production codebase.

Before Blacksmith existed, most companies ran those jobs themselves on rented servers from Amazon Web Services, Microsoft Azure or Google Cloud. Blacksmith took a different route. It bought its own servers and built a CI cloud spanning multiple global locations, writing its own software to run the jobs. It also automates much of the manual setup work that each new piece of code previously required.

The timing explains the traction. AI coding assistants such as Cursor, Anthropic's Claude and OpenAI's Codex have made writing code "extremely easy," Jayaprakash wrote in a blog post announcing the round. He noted that developers once split their time roughly in half between writing code and waiting for builds and tests to finish. The first half is now nearly free.

"Now the bottleneck has shifted to the second piece, which is: how do I actually validate all this code?" Jayaprakash told Fortune.

How big is the bottleneck?

Anthropic said last month that its code validation workload has grown more than 25-fold in six months as Claude took over most coding duties from its human developers. Blacksmith has not eliminated that bottleneck, but it eases it. "Companies bring us their CI workloads and we run them faster than they could anywhere else, with zero operational overhead," Jayaprakash said.

CI demand is violently unpredictable. It can jump from zero to tens of thousands of CPUs, then collapse when testing finishes. Jayaprakash said Blacksmith built its infrastructure specifically to absorb that volatility, and owning hardware rather than renting it gives the company more control over performance.

That ownership carries a cost. Blacksmith is now exposed to the global shortage of components such as memory. Capacity planning has become one of the hardest parts of running the company, Jayaprakash said, because demand spikes whenever a new frontier AI model launches. When Anthropic debuted Claude Fable 5 in July, Blacksmith's CI workload volume rose more than 40% in a single day.

What do the numbers say about traction?

More than 10,000 companies now use the platform, up from around 5,000 in August. Named customers include LangChain, Supabase and Granola.

The usage curve is steeper still. In early 2026, Blacksmith ran about 5 million code checks per week. That figure now sits at about 90 million, and annual recurring revenue has grown 17 times over the same period. Jayaprakash puts revenue in the "tens of millions of dollars," with some of the largest clients spending more than $1 million a year.

What comes next?

Blacksmith will spend most of the new capital on servers to expand its global CI cloud. It also plans to grow its roughly 40-person team to 75 by the end of the year.

One risk sits on the horizon. The same AI model vendors whose coding tools fuel Blacksmith's growth could move into code validation themselves and become direct competitors. For now, the startup is growing fast enough — and the flood of AI-generated code is rising fast enough — that investors are pricing that risk at a billion dollars.