Anthropic has announced the acquisition of the developer tools startup Stainless, which previously served as shared infrastructure for multiple AI companies, including OpenAI, Google, and Cloudflare. With the deal finalized, these tools will transition from general-purpose services to internal capabilities of Anthropic.
Transaction amount undisclosed
Anthropic has not disclosed the acquisition price. The Information previously reported that Anthropic was in talks to acquire Stainless, with the deal potentially exceeding $300 million.
Stainless was founded in 2022 by Alex Rattray, a former Stripe engineer, and is headquartered in New York. The company has received support from Sequoia Capital and Andreessen Horowitz.
The core product is automatic SDK generation.
Stainless's core product is an automatically generated and maintained SDK—a software toolkit commonly used by developers to call APIs. It directly converts API specifications into production-ready SDKs and supports multiple languages, including Python, TypeScript, Kotlin, Go, and Java.
The value of these tools lies in their ability to automatically update the SDK when the API changes, reducing manual maintenance efforts. For AI companies that frequently iterate their interfaces, this significantly lowers development costs.
Competitors will lose access to the same tool source.
Anthropic has stated that it will gradually shut down Stainless’s existing hosted products, including its SDK generation service. SDKs that have already been generated remain the property of the customers, who may continue to modify and extend them.
However, with the exit of托管 services from the market, Stainless’s role as an independent infrastructure provider will also come to an end. The report indicates that this means companies such as OpenAI, Google, Replicate, Runway, and Cloudflare will no longer be able to access these services through the same set of tools.
Anthropic also stated that its official SDK has been generated by Stainless software since the early days of the API business. This acquisition further demonstrates that AI model companies are bringing key development tools back in-house.