A startup that checks AI-written code just jumped from a $60 million to a $550 million valuation in under a year

Key points

• Blacksmith raised a $45 million Series B in 2025, valuing the company at $550 million, up from $60 million less than a year ago.
• The startup grew from roughly 700 customers to more than 5,000 in under twelve months.
• Revenue reached "tens of millions of dollars" annually, with some customers spending over $1 million a year on the platform.
• Blacksmith now employs around 30 people, up from just 10 when it hit its first $10 million revenue milestone.
• Competitors include GitHub Actions, Amazon Web Services, Microsoft Azure and Google Cloud.

AI tools can write code faster than most human developers. That sounds like a win. But someone still has to check whether that code actually works, and right now, that checking part is a serious bottleneck.

Blacksmith, a San Francisco startup founded in 2024, thinks it has the answer. This week it announced a $45 million Series B funding round, led by venture firm Peak XV Partners, with existing backers GV and Y Combinator also putting money in. Its total funding now stands at $58.5 million.

The valuation jump is striking. Less than a year ago, the company raised a $10 million Series A at a $60 million valuation. Today it is valued at $550 million. That is nearly a tenfold increase in under twelve months.

What does Blacksmith actually do?

Blacksmith helps software teams catch bugs and errors before code goes live. It started as a platform for running automated software builds and tests, a process sometimes called continuous integration (CI), which basically means machines automatically double-check code every time a developer makes a change. More recently it added a tool called Codesmith, an AI agent (software that can carry out multi-step tasks on its own) that can automatically fix code that fails those checks.

CEO Aditya Jayaprakash told TechCrunch AI that the rise of AI coding tools like Cursor, OpenAI's Codex and Anthropic's Claude Code is creating more code than ever, but not necessarily better code. "Validating code is still a bottleneck, and it's an even bigger bottleneck because people are writing even more," he said.

More code means more things to check. That is Blacksmith's pitch.

Is the growth real?

The numbers suggest it is, though context matters. The company grew from about 700 customers to more than 5,000 in under a year, and clients include financial software company Mercury and expense-management platform Expensify. Revenue grew from a $10 million annual run rate (the pace at which money was coming in, projected over a full year) to "tens of millions of dollars," though Jayaprakash declined to give a precise figure.

The company achieved that first milestone with just 10 employees. It now has around 30.

Should anyone be worried about the competition?

Blacksmith is not alone here. GitHub Actions, Amazon Web Services, Microsoft Azure and Google Cloud all offer code-testing and validation tools. Cursor and Anthropic bake similar checks into their own products. That is a crowded field for a startup with 30 people.

Jayaprakash says Blacksmith competes on speed and price, and plans to expand into a fuller suite of tools covering writing, validating and merging code. Whether that is enough to hold ground against the big cloud players is the real question hanging over a $550 million valuation.

For developers already relying on AI to write their code, the bigger takeaway is simple: the check-your-work step did not disappear. It just got more complicated.