Anthropic strengthens Claude Code with Bun acquisition

Anthropic has acquired JavaScript toolchain Bun to enhance the speed, stability and scalability of Claude Code, its fast-growing AI coding assistant already used by global enterprises. The move aims to strengthen Anthropic’s developer infrastructure amid rising AI-driven software development.

Anthropic has announced the acquisition of Bun, the high-performance JavaScript toolchain, as it accelerates efforts to support soaring demand for its AI coding assistant, Claude Code. The deal comes as the company reports a sharp rise in enterprise adoption, making Claude Code one of the fastest-growing developer tools globally.

Claude Code, which became widely available in May 2025, is now used by major companies including Netflix, Spotify, KPMG, L’Oréal and Salesforce. Anthropic says the tool crossed USD 1 billion in run-rate revenue in November, underscoring the rapid shift toward AI-augmented software development.

Why Bun fits into Anthropic’s strategy

Bun, launched in 2021, reimagines the JavaScript toolchain by combining a runtime, package manager, bundler and test runner in a single system. Its emphasis on speed has made it popular among teams building AI-enabled applications, with more than seven million monthly downloads and over 82,000 GitHub stars.

Anthropic confirmed that Bun has quietly powered several components of Claude Code for months, including its native installer. The acquisition formalizes this partnership and positions Bun as a core part of Anthropic’s engineering stack.

What developers can expect

Mike Krieger, Chief Product Officer at Anthropic, said Bun embodies the kind of “technical excellence” the company wants to deepen across its products. He added that integrating Bun will help Claude Code scale to meet growing demand from enterprises adopting coding agents.

Anthropic said Bun will remain open source under the MIT license, with ongoing improvements planned for JavaScript and TypeScript developers. As it becomes more tightly woven into Claude Code, users can expect faster performance, greater reliability and expanded features.

The road ahead

Anthropic says the acquisition aligns with its broader approach of strengthening foundational technologies to support next-generation software development. With coding agents gaining traction globally, Bun is expected to help Anthropic handle heavier workloads and maintain its momentum in the competitive AI developer ecosystem.