Anthropic has acquired Stainless, a developer tools startup that has also been used by rivals including OpenAI and Google. TechCrunch reported on May 18 that the deal will bring one of the AI industry's key pieces of developer infrastructure under Anthropic.

The terms were not disclosed. The Information reported last week that Anthropic was in talks to buy Stainless, which has received investment from Sequoia Capital and Andreessen Horowitz, for more than $300 million.

Anthropic plans to stop operating all of Stainless’ hosted service products. This includes its SDK generator. Existing customers will retain ownership of SDKs they have created so far and can freely modify or extend them.

Stainless was founded in New York in 2022 by Alex Rattray (알렉스 래트레이), an engineer who previously worked at Stripe. Stainless drew attention for software that automatically creates and manages SDKs for multiple languages including Python, TypeScript, Kotlin, Go and Java based on API specifications. When an API changes, the SDK is updated automatically, reducing customers' manual maintenance burden.

It was particularly useful for companies developing AI agents. OpenAI, Google, Replicate, Runway and Cloudflare have also used Stainless tools. TechCrunch said that after the acquisition, Stainless tools will not be provided to competitors and will be used only inside Anthropic.