As artificial intelligence accelerates the pace of coding, the next major hurdle in software development lies in testing and validating the growing volume of generated code. Blacksmith is positioning itself to seize this opportunity, having just secured $45 million in fresh funding. The Series B round, led by Peak XV Partners, values the company at $550 million—a significant leap from the $60 million valuation it held during its $10 million Series A less than a year ago. Existing backers GV and Y Combinator joined the round as well, pushing Blacksmith's total funding to $58.5 million.

Founded in 2024, Blacksmith focuses on helping businesses build, test, and verify software before it goes live. The startup now supports over 5,000 customers, including Mercury, Supabase, Clerk, Ashby, and Expensify—a sharp rise from just 700 customers under a year ago, according to co-founder and CEO Aditya Jayaprakash in an exclusive conversation.

The surge in AI-powered coding tools like Cursor, OpenAI’s Codex, and Anthropic’s Claude Code has made it much easier for teams to produce code at scale. However, the reliability of that code remains uncertain. "Validating code is still a bottleneck, and it’s an even bigger bottleneck because people are writing even more," Jayaprakash explained.

Initially, Blacksmith operated as a cloud provider for continuous integration (CI) workloads, enabling companies to run builds and tests that verify code before deployment. Since then, it has expanded its offerings with Codesmith, an AI coding agent designed to automatically resolve failed code checks. Jayaprakash noted that Blacksmith hit a $10 million annualized revenue run rate with just 10 employees, and has since scaled its team to around 30 people while growing revenue to "tens of millions of dollars." He declined to provide a more specific updated ARR figure, though he confirmed that some of its largest clients now spend over $1 million annually on the platform.

Despite this rapid progress, Blacksmith faces intense competition in a crowded space. Key rivals include GitHub Actions, Cursor Automations, validation features embedded in Codex and Claude Code, numerous emerging startups, and AI-driven code-testing solutions from Amazon Web Services, Microsoft Azure, and Google Cloud. Jayaprakash emphasized that his company differentiates itself through faster test execution and competitive pricing.

Looking forward, Blacksmith intends to broaden its toolkit, aiming to help developers write, validate, and merge code more efficiently across a wider range of coding workflows.