Blacksmith's $1B Tool Checks AI-Written Code for Errors

Blacksmith, a company that helps businesses test their software more efficiently, announced on Wednesday that it has raised $66 million in new funding. The investment round was led by Sequoia and values the company at $1 billion, making it a "unicorn" (a private startup worth over a billion dollars). Blacksmith's tools are especially important now because more and more code is being written by AI, and companies need to make sure that code works correctly.

Blacksmith's CEO, Aditya Jayaprakash, said the company was founded to make continuous integration (CI)—the process of building, testing, and merging code changes—"less painful." He noted that most companies struggle to keep up with the volume of CI they need to run, especially when AI is writing so much code. "As agents write more of the world's software, the question that matters is whether it can be trusted," he added. Blacksmith's platform automatically runs checks on code to catch errors early, saving companies time and money.

The company's growth has been rapid. Its annual recurring revenue has grown 17 times over the past year, and it has run over 90 million CI jobs (individual automated code checks). Customers include Mercury and Granola. Just two months ago, Blacksmith raised a $45 million Series B at a $550 million valuation, and a year ago it was valued at only $60 million. To date, the company has raised $125 million. This surge in valuation shows investors believe Blacksmith is solving a critical problem as AI-generated code becomes more common.

For everyday people, Blacksmith's success means the apps and websites you use are more likely to work smoothly, even as AI writes more of the code behind them. It also signals that AI is changing how software is built—and creating new opportunities for companies that help ensure quality.