Blacksmith hits $550M valuation after 5,000 customers flock to code testing

Nine months ago, Blacksmith was a $60 million startup with 700 customers. Today it’s worth $550 million and counts more than 5,000 companies on its platform. That kind of growth curve tells you everything about where software development is heading.

The startup just closed a $45 million Series B led by Peak XV Partners, with GV and Y Combinator participating. Total funding now stands at $58.5 million. CEO Aditya Jayaprakash, who co-founded the company in 2024, pinned the momentum on a simple dynamic: AI tools like Cursor, OpenAI’s Codex, and Anthropic’s Claude Code have made writing code trivial, but somebody still has to make sure that code actually works. “Validating code is still a bottleneck, and it’s an even bigger bottleneck because people are writing even more,” he said.

Blacksmith began as a cloud provider for continuous integration workloads — the builds and tests that catch broken code before it ships. The company has since launched Codesmith, an AI agent that automatically fixes failed checks. Revenue hit a $10 million annualized run rate with just 10 employees, and Jayaprakash says that figure has grown to “tens of millions” with a team of around 30. Some enterprise customers now spend more than $1 million annually. Mercury, Supabase, Clerk, Ashby, and Expensify are among the names on the roster.

The competition, though, is not exactly sparse. GitHub Actions, Cursor Automations, native validation features in Codex and Claude Code, plus testing services from AWS, Azure, and Google Cloud all want this market. Blacksmith’s pitch boils down to speed and price. Jayaprakash is betting that as code generation becomes commoditized, the real leverage shifts to whoever can validate and merge changes fastest. He plans to expand Blacksmith into a broader suite of developer tools covering writing, validation, and merging — a full pipeline play. Whether that’s enough to fend off the hyperscalers is the open question. Nine months from now, the answer will be a lot clearer.