Direct Acquisition of OpenAI's SDK Contractor! Anthropic Buys Stainless at Double Valuation

According to monitoring by Beating, Anthropic has officially announced the acquisition of developer tools startup Stainless. This company specializes in using AI to automatically package complex APIs into cross-language SDKs. After the transaction is completed, the Stainless team will be fully integrated into Anthropic, focusing on enabling Claude to connect with external tools and data. This deal effectively gives Anthropic direct control over a competitor's underlying toolchain. Due to the high engineering resource costs of maintaining multi-language SDKs, OpenAI previously abandoned internal development and fully transitioned to Stainless. Although there are alternative solutions like Speakeasy and LibLab on the market, the top three major model companies (OpenAI, Google, Anthropic) are all currently using Stainless to generate SDKs. The specific transaction amount has not been disclosed officially. However, according to a prior report by *The Information*, the acquisition price was at least $300 million, effectively doubling Stainless's valuation from $150 million in December of last year. In addition to serving the three major model companies, Stainless had previously developed supporting tools for Anthropic's MCP (Model Context Protocol). This marks Anthropic's fourth acquisition in six months: following last year's purchase of the JavaScript runtime Bun, it has also successively acquired computer operating system company Vercept and AI biotech company Coefficient Bio. [Original Link]