With Claude Code soaring to $1B run-rate, Anthropic buys Bun—one of the fastest JavaScript runtimes—to fuel the next era of AI-native software development.
Claude has quickly become one of the world’s most capable AI models for developers, startups and enterprises — and Claude Code is redefining how software gets built. In November, just six months after its public debut, Claude Code reached $1 billion in run-rate revenue, marking one of the fastest enterprise AI ramps to date.
Anthropic announced it is acquiring Bun, the breakthrough JavaScript runtime, to accelerate that momentum even further.
Bun has become a cornerstone for modern software engineering. Founded by Jarred Sumner in 2021, the all-in-one toolkit — runtime, package manager, bundler and test runner — has earned a reputation for speed, performance and reliability that outpaces leading alternatives. As AI-led software development grows, Bun has emerged as critical infrastructure, helping teams build and test applications at remarkable velocity.
For Claude Code users, the acquisition promises faster performance, improved stability and new capabilities. Anthropic says it will continue investing in Bun as the premier JavaScript runtime while deepening its integration into Claude Code’s workflows.
Since launching in May 2025, Claude Code has evolved from an internal experiment into a core tool for some of the world’s largest enterprises, including Netflix, Spotify, KPMG, L’Oréal and Salesforce. Bun has been central to scaling that infrastructure, including powering Claude Code’s new native installer.
“We’ve been close partners with Bun for many months,” Anthropic said. “The team shares our focus on rethinking the developer experience and building useful, innovative tools.”
“Bun represents exactly the kind of technical excellence we want to bring into Anthropic,” said Mike Krieger, Chief Product Officer at Anthropic. “Jarred and his team rethought the entire JavaScript toolchain from first principles while staying grounded in real use cases. Claude Code hit $1 billion in run-rate revenue in just six months, and bringing the Bun team inside Anthropic lets us build the infrastructure to compound that momentum and keep pace with exponential AI adoption.”
Bun’s growth speaks for itself: more than 7 million monthly downloads, 82,000+ GitHub stars, and adoption from companies like Midjourney and Lovable to boost speed and productivity.
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Anthropic says the acquisition aligns with its disciplined approach to M&A — prioritizing technologies that strengthen its enterprise AI leadership, reinforce technical excellence and align with its principles and mission.
Bun will remain open source and MIT-licensed, and Anthropic plans to continue developing it as the runtime, bundler, package manager and test runner of choice for JavaScript and TypeScript developers.
The company says Bun will play a foundational role in building the infrastructure for the next generation of software — and in keeping Claude the platform of choice for coders and AI-powered teams.
Developers interested in joining Anthropic’s engineering organization can learn more on the company’s careers page.
