IBL News | New York
Anthropic acquired Stainless this month, a leading firm specialized in SDKs and MCP server tooling, a transaction that takes place in a context where AI models are shifting from models that answer to agents that act.
Analysts estimated that Anthropic paid over $300 million for this company, which is backed by Sequoia Capital and Andreessen Horowitz, although the official terms of the deal were not disclosed.
Founded in 2022 and based in New York, Stainless has powered Anthropic’s SDK since the earliest days of its API.
Many companies rely on Stainless to generate SDKs, CLIs, and MCP servers—the libraries, command-line tools, and connectors developers use to interact with APIs.
Stainless turns an API spec into SDKs across TypeScript, Python, Go, Java, and more. Stainless’s software is also widely used by rivals OpenAI and Google, as well as others such as Replicate, Runway, and Cloudflare.
Going forward, the Stainless tools will only be available to Anthropic, not its competitors.
Therefore, the acquisition will take a key infrastructure supplier out of the hands of Anthropic’s competitors.
“Agents are only as useful as what they can connect to. We’re excited to bring the Stainless team into Anthropic to advance Claude’s ability to connect to data and tools,” said Katelyn Lesse, Head of Platform Engineering at Anthropic — a company that created MCP to make agent connectivity possible.