By Hamza Faisal

Blacksmith, a startup that runs the testing infrastructure companies use before shipping code, has raised a $66 million Series C round led by Sequoia Capital that values the company at $1 billion — just two months after its last funding round.

The round, announced Wednesday, more than doubles the $550 million valuation Blacksmith received in August, when it closed a $45 million Series B led by Peak XV Partners. A year ago, the company was worth $60 million after raising a $10 million Series A. Total funding now stands at roughly $125 million, with Premji Invest joining the new round alongside existing investors Peak XV, GV, and Y Combinator.

The bottleneck moved downstream

Blacksmith's pitch is simple: artificial intelligence made writing code cheap, so testing it became the constraint. Coding agents now write pull requests far faster than most testing pipelines can keep up with. Every one of those pull requests still has to compile, pass tests, and clear a continuous-integration pipeline before a human merges it.

Co-founder and CEO Aditya Jayaprakash, who started the company in 2024 with Aayush Shah and Aditya Maru, said Blacksmith was founded to make continuous integration "less painful." In a blog post announcing the round, he wrote that "most companies are struggling to keep up with the volume of CI they need to run" as AI writes more code — adding that "as agents write more of the world's software, the question that matters is whether it can be trusted."

Twice as fast, half the cost

Blacksmith is built as a faster replacement for GitHub Actions runners. It boots jobs into Firecracker microVMs on bare-metal, gaming-grade CPUs instead of shared cloud infrastructure — a setup the company says runs pipelines roughly twice as fast at about 60 percent lower cost than standard GitHub Actions.

The numbers behind the valuation jump are striking. Blacksmith says CI jobs on its platform grew from 5 million a week to more than 90 million a week since January 2026, and annual recurring revenue has grown 17-fold over the same stretch. More than 10,000 companies now use the service, including Mercury, Granola, Ashby, Handshake, and LangChain. Fortune reported that revenue is in the tens of millions and that its largest customers spend over $1 million a year each.

The gold-rush pattern holds

Blacksmith fits the classic infrastructure-investing pattern: every gold rush reprices its tools. AI made code abundant, verification became the scarce resource, and the money followed the new constraint. The company plans to use the new funds to grow its team and expand its compute footprint across data centers in the United States and Europe, where it already manages nearly 10 megawatts of compute.

Whether the bet pays off depends on whether AI-written code keeps flooding in faster than pipelines can absorb it. For now, investors are betting that the bottleneck — and the company that owns it — is here to stay.

By Hamza Faisal