Anthropic Acquires Stainless for $300M+ — Cuts Off the SDK Generator Used by OpenAI, Google, and Cloudflare

Anthropic / Hacker News·high signal

Anthropic announced the acquisition of Stainless, the SDK generation startup founded by former Stripe engineer Alex Rattray, for over $300 million — more than double its December 2025 valuation. Stainless has powered every official Anthropic SDK since the API's earliest days and is also used by OpenAI, Google, and Cloudflare. The entire Stainless team joins Anthropic to focus on agent-tool connectivity, while all hosted Stainless products including the public SDK generator will be wound down — 493 points and 350 comments on HN.