AI tools like Cursor, Codex, and Claude Code can now write code faster than ever. The bottleneck has shifted from writing software to proving it works, and a startup built around that problem is suddenly worth a lot more money.
Blacksmith, founded in 2024, said it has raised a $45 million Series B led by Peak XV Partners at a $550 million valuation. That is close to ten times the $60 million mark it carried when it closed a $10 million Series A less than a year earlier. Existing investors GV and Y Combinator also joined the round, bringing total funding to $58.5 million.
The company helps teams build, test, and verify code before it ships. Co-founder and CEO Aditya Jayaprakash said Blacksmith now serves more than 5,000 customers, including Mercury, Supabase, Clerk, Ashby, and Expensify, up from just over 700 a year ago.
Why testing, not writing, became the constraint
The rise of AI coding assistants made generating code dramatically easier, but the quality of that output is not guaranteed. "Validating code is still a bottleneck, and it's an even bigger bottleneck because people are writing even more," Jayaprakash said.
Blacksmith began as a cloud provider for continuous integration, the pipeline that runs builds and tests before code reaches production. It has since expanded with Codesmith, an AI coding agent that can automatically fix failed checks.
Jayaprakash said the company reached a $10 million annualized revenue run rate with about 10 employees, has grown to roughly 30 people, and now generates "tens of millions of dollars" in revenue. He declined to give an exact updated figure but said some of its largest customers spend more than $1 million a year on the platform.
A crowded field
Blacksmith is not alone. Its competitors include GitHub Actions, Cursor Automations, and validation features baked into Codex and Claude Code, along with a set of other startups and the AI code-testing services offered by Amazon Web Services, Microsoft Azure, and Google Cloud. Jayaprakash said Blacksmith is competing on test speed and price.
Looking ahead, he said the company plans to broaden into a wider suite of coding tools aimed at helping developers write, validate, and merge software faster.
Why it matters
The funding shows where the money is moving in the AI developer-tools market. As models lower the cost of producing code, the expensive, slow work of checking that code is shifting to agents. Startups that can make validation both fast and affordable are attracting the valuations usually reserved for the model makers themselves.
Sources:
- TechCrunch: Blacksmith's valuation jumps almost 10x in less than a year
- Blacksmith: company site
