capital · May 21, 2026
Anthropic Acquires Stainless Developer Tools Startup for Over $300 Million
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Anthropic acquired Stainless, a developer tools startup founded by former Stripe engineer Alex Rattray, on May 18, 2026. Stainless generates production-ready SDKs from API specifications and powers the official SDKs for OpenAI, Google, Cloudflare, Meta, Replicate, Runway, and Anthropic itself since its earliest API days. Anthropic will wind down all hosted Stainless products including the SDK generator that rivals depend on, while customers retain rights to their previously generated SDKs. Anthropic spokesperson confirmed the acquisition after The Information reported talks valued above $300 million last week.
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