Anthropic brings Bun in-house, the runtime powering Claude Code’s $1B ARR

Dec 3, 2025

Anthropic

Anthropic has acquired Bun, the popular JavaScript and TypeScript runtime and toolchain. The company says the deal strengthens the infrastructure behind both its coding tool Claude Code and the Claude Agent SDK. Bun already powers these systems today, and Claude Code ships to millions of users as a Bun executable.

Anthropic also highlighted a major milestone: in November 2025, just six months after its public launch in May, Claude Code reached an annualized revenue of one billion dollars.

Anthropic brings Bun in-house, the runtime powering Claude Code’s $1B ARR

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