Anthropic acquired Bun, the JavaScript runtime — its first acquisition, on undisclosed terms. Bun bundles a runtime, package manager, bundler, and test runner into one toolkit; founded by Jarred Sumner in 2021, it had over seven million monthly downloads and more than 82,000 GitHub stars. Claude Code ships as a Bun executable, so Anthropic was taking in the team behind infrastructure its flagship product depends on. The announcement also disclosed that Claude Code had reached $1 billion in run-rate revenue six months after its May 2025 general availability. Anthropic said Bun would remain open source under the MIT license and that it would keep investing in it as a tool for all developers.