Blacksmith hits $1 billion valuation after $66 million Series C led by Sequoia

Blacksmith, a startup that runs the machinery companies use to test their code before release, is now worth $1 billion. The new mark comes from a $66 million Series C round led by Sequoia Capital.

According to Fortune, the round lands about two months after Blacksmith raised a $45 million Series B at a $550 million valuation.

The round, by the numbers

The Series C pushes Blacksmith’s total funding to about $124.5 million, according to Fortune. Separate research findings put the exact Series C amount at approximately $66.26 million.

Sequoia led this round. The earlier Series B was led by Peak XV Partners, with GV (formerly Google Ventures) and Y Combinator also participating. Before the Series C, the company had raised a total of approximately $58.5 million.

The valuation trajectory is steep. Blacksmith sat at roughly $60 million after its Series A, then jumped to $550 million with the Series B. The latest round nearly doubles that figure.

The underlying business metrics help explain the enthusiasm. Revenue has climbed from the early single-digit millions to the tens of millions, per the research findings. Some enterprise customers now spend more than $1 million a year with the company.

The customer base has grown from approximately 700 to 800 in late 2025 to somewhere between 5,000 and 6,000 or more. Named customers include Supabase and Expensify. Headcount, meanwhile, went from about 10 employees to about 30.

What Blacksmith actually does

Every time a developer submits a change, automated tests run to make sure nothing breaks. Those tests need computing power to run on, and the machines that execute them are called runners. Blacksmith sells high-performance cloud runners plus caching tools designed specifically for these CI workloads.

The company positions itself as a quicker, cheaper alternative to running those jobs on GitHub Actions, the default automation tool for many developers using GitHub.

Blacksmith was founded in 2024 in San Francisco by Aditya (JP) Jayaprakash, who serves as CEO, along with Aayush Shah and Aditya Maru. The trio came through Y Combinator’s Winter 2024 batch. They started with bare-metal CI runners for GitHub Actions, meaning dedicated physical servers rather than shared virtual machines.

The company has since expanded into AI-assisted tooling. Its Codesmith coding agent automatically diagnoses failed code checks and attempts to fix them.

The AI coding boom is a testing boom

According to the research findings, CI job volume on Blacksmith has grown by 5% to 10% every week since early 2026, tracking the rise in AI coding adoption.

What this means for developers, investors, and rivals

Competition is another factor to watch. Blacksmith’s pitch is built around being faster and cheaper than GitHub Actions’ own runners. That makes its fortunes partly tied to how a much larger platform chooses to price and improve its own offering.

The Codesmith agent suggests the company sees that risk and wants to move up the value chain. Selling raw compute for tests is useful. Selling software that understands why tests fail and fixes them is stickier, and potentially harder for a platform owner to replicate quickly.