Anthropic has acquired the dev tools startup used by OpenAI, Google, and Cloudflare

Anthropic has acquired Stainless, a startup that automates SDK generation and maintenance for APIs, in a deal reportedly worth over $300 million.

Anthropic said it will shut down Stainless’s hosted products, while customers will keep ownership of the SDKs generated with the tool.

The acquisition takes a key SDK infrastructure provider off the market and strengthens Anthropic’s control over developer tooling for AI agents and API integrations.