Sequoia Leads $66 Million Series C in Blacksmith at $1 Billion Valuation

Blacksmith has raised $66 million in Series C funding led by Sequoia Capital at a $1 billion valuation. The round takes the AI code testing platform's total capital raised to $125 million.

Premji Invest joined the round. Existing investors Peak XV Partners, Google Ventures (GV) and Y Combinator also participated, the company said.

The deal marks a sharp step up from Blacksmith's last raise. In its Series B, the company secured $45 million led by Peak XV Partners at a $550 million valuation, with GV and Y Combinator participating. The Series C nearly doubles that figure in valuation terms.

What does Blacksmith actually do?

Blacksmith sells infrastructure that helps software development teams build and test code. Its platform runs continuous integration (CI) workflows. Developers use those workflows to check code and catch issues before merging changes into software projects.

The company claims its platform runs CI jobs twice as fast as alternatives and at an average cost 60% lower. More than 10,000 companies use the platform, including Ashby, Granola, Handshake and LangChain.

The growth numbers explain why Sequoia wrote the check. Blacksmith said its annual recurring revenue has grown 17 times since January 2026. Weekly CI jobs processed through the platform rose from 5 million to more than 90 million over the same period.

That is an 18-fold increase in workload. Very few infrastructure businesses absorb that kind of ramp without heavy capital spending, which is where the new money goes.

Where will the money go?

Blacksmith currently manages nearly 10 megawatts of computing capacity across data centers in the United States and Europe. It plans to increase that capacity at least fivefold in 2027 to support rising demand for its services.

The fresh capital will fund two things: workforce expansion and computing infrastructure, as the company scales operations.

Why is CI infrastructure hot right now?

The company operates in the software development infrastructure market, where demand for automated code testing and validation is climbing alongside the adoption of AI coding agents. As developers use AI tools to generate more code, businesses need infrastructure that can test those changes quickly and reliably before deployment.

The mechanism is simple. AI agents produce code far faster than human developers. Every line of machine-generated code still needs validation before it ships. That turns code testing from a background task into a bottleneck, and vendors who remove the bottleneck capture the budget.

How did Blacksmith build to this point?

The company's funding history shows a steady climb through the standard venture stages:

• $500,000 pre-seed from Y Combinator
• $3.5 million seed backed by GV and Y Combinator
• $10 million Series A led by GV
• $45 million Series B led by Peak XV Partners
• $66 million Series C led by Sequoia Capital

Blacksmith has used its funding to expand the code testing platform, strengthen its infrastructure and support growing demand for faster, more cost-efficient software development workflows.

The Series C values the company at $1 billion. Whether that valuation holds depends on one variable the source makes plain: whether Blacksmith can quintuple its computing capacity in 2027 fast enough to keep pace with the AI-driven demand its own growth charts already show.