Claude

Anthropic Acquires JavaScript Runtime Bun - Claude Code Hits $1B Revenue in 6 Months

Anthropic acquires Bun, the JavaScript runtime, to strengthen infrastructure for Claude Code. This strategic move signals a new era in AI-powered developer tools.

Anthropic Claude Code Bun JavaScript TypeScript Acquisition Developer Tools AI Coding Open Source Infrastructure

Claude Code Reaches $1 Billion Run-Rate Revenue in Just 6 Months

Anthropic announced on December 2, 2025, that it has acquired Bun, the breakthrough JavaScript runtime. This acquisition comes as the company’s AI coding tool, Claude Code, continues its extraordinary growth trajectory.

Claude Code, which became generally available in May 2025, has reached $1 billion in annual run-rate revenue in just six months. Major enterprises including Netflix, Spotify, KPMG, L’Oréal, and Salesforce have already adopted Claude Code as a critical tool for their development workflows.

What is Bun?

Bun is a JavaScript and TypeScript runtime created by Jarred Sumner that offers significant advantages over traditional Node.js:

  • Blazing Fast Performance: Faster installation, building, running, and testing
  • All-in-One Toolkit: Combines runtime, package manager, bundler, and test runner
  • Enhanced Developer Experience: Simple and intuitive design

Bun has already surpassed 5 million monthly downloads, rapidly gaining traction in the developer community.

The Strategic Rationale

Anthropic and Bun have been close partners for months, with Bun already powering Claude Code’s CLI (command-line interface). The acquisition enables:

  1. Enhanced Claude Code Performance: Faster and more stable execution environment
  2. Strengthened Claude Agent SDK: Infrastructure foundation for future AI coding products
  3. Improved Development Workflows: Better workflow integration with Claude Code

Open Source Commitment Continues

Bun will remain open-source and MIT-licensed after the acquisition. The Bun team has explicitly stated:

  • Bun stays open-source and MIT-licensed
  • The same team continues development
  • Public development style remains unchanged
  • The mission to make JavaScript/TypeScript faster continues

Jarred Sumner describes this relationship as similar to “Chrome/V8 or Safari/JavaScriptCore” — a browser-engine relationship where the runtime maintains its identity while powering a flagship product.

Industry Implications

This acquisition demonstrates that AI companies are now investing in entire developer infrastructure stacks, not just model development.

Anthropic’s annual revenue run-rate has grown dramatically:

  • January 2025: $1 billion
  • August 2025: $5 billion
  • October 2025: $7 billion

Claude Code has become a key driver of this growth.

In an era where AI writes and tests code at machine speed, runtime performance directly impacts user experience. This acquisition signals that the AI coding tools race has entered a new phase.