Anthropic Acquires Stainless, Enhancing AI Development Tools

• •Anthropic acquired Stainless for over $300 million to enhance its SDK capabilities.
• •Stainless has powered every official Anthropic SDK since the beginning of its API.
• •The acquisition will limit access to Stainless's tools for Anthropic's competitors.

On May 18, 2026, Anthropic announced its acquisition of Stainless, a startup specializing in SDK generation for AI applications. Founded in 2022, Stainless has been instrumental in creating SDKs for major AI companies, including Anthropic itself. The acquisition is valued at over $300 million and will remove a key infrastructure supplier from Anthropic's competitors. Stainless's technology automates the creation and maintenance of SDKs across multiple programming languages, streamlining the integration of APIs for developers. Anthropic plans to wind down all hosted Stainless products but assures existing customers retain ownership of their generated SDKs. This acquisition is expected to enhance Anthropic's capabilities in developing AI agents that can connect to various software tools. The deal reflects the growing importance of robust development tools in the AI sector.