Anthropic, the leading company in AI-driven development tools, officially announced it had acquired Bun, a high-performance JavaScript runtime, as the company scales its flagship coding product, Claude Code. This strategic acquisition comes at a critical point just six months after its public debut, when Claude Code reached the impressive milestone of generating $1 billion in annualized run-rate revenue.
Since general availability in May 2025, Claude Code has rapidly developed from an internal engineering initiative into a mission-critical coding assistant for enterprises the world over. Early customers who have adopted Claude Code to drive efficiency in development workflows include Netflix, Spotify, KPMG, L’Oréal, and Salesforce.
Bun, founded in 2021 by Jarred Sumner, offers a broad toolkit that includes all the commonly used runtime, package manager, bundler, and test runner rolled into one. Characterized for rewriting the rules on speed and performance for developing with JavaScript and TypeScript, Bun has grown to be one of the central pieces of Claude Code’s infrastructure. In fact, Anthropic had already been partnering with Bun for several months-a partnership that helped drive the launch of Claude Code’s native installer and enhance underlying workflows.
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On the acquisition, Mike Krieger, Chief Product Officer at Anthropic, said, “Bun represents exactly the kind of technical excellence we want to bring into Anthropic. Jarred and his team rethought the entire JavaScript toolchain from first principles while remaining focused on real use cases. Claude Code reached $1 billion in run-rate revenue in only 6 months, and bringing the Bun team into Anthropic means we can build the infrastructure to compound that momentum and keep pace with the exponential growth in AI adoption.”
Anthropic positions this acquisition as a major milestone in its long-term vision for improving AI-powered software engineering. Integrating Bun’s fast, all-in-one runtime directly into Claude’s platform will drive improvements in performance and stability and unlock new capabilities to be made available to developers. Bun will remain open-source under the MIT license, continuing to serve JavaScript and TypeScript developers even as it helps power Claude’s growth in the future.
The acquisition underscores Anthropic‘s commitment to bolstering its offerings in the enterprise AI segment and reflects a broader industrywide trend: as the rate of AI adoption increases, ownership of key underlying development infrastructure is becoming a competitive imperative.