NEW YORK — Anthropic announced that it has acquired Stainless, a New York-based startup whose software automates the creation and maintenance of software development kits, or SDKs. The terms of the deal were not disclosed, though Anthropic had been in talks to acquire Stainless for more than $300 million.

Stainless was founded in 2022 by Alex Rattray and is backed by Sequoia Capital and Andreessen Horowitz. Rattray developed software that converts API specifications into production-ready SDKs across multiple programming languages including Python, TypeScript, Kotlin, Go, and Java. The platform automatically updates SDKs as APIs change and eliminates the manual maintenance process.

Companies building AI agents that connect to external software and complete tasks on behalf of users, including Anthropic, OpenAI, Google, Replicate, Runway, and Cloudflare, use Stainless's SDK tools. According to Anthropic, Stainless software has powered the generation of every official Anthropic SDK since the earliest days of its API.

Following the acquisition, Stainless's dev tools will only be available to Anthropic, not to its competitors. Anthropic will wind down all hosted Stainless products, including its SDK generator. The company said Stainless customers will still own the SDKs they have generated to date and have full rights to modify and extend them.

"I started Stainless because SDKs deserve as much care as the APIs they wrap," Rattray said. "Anthropic was one of the first teams to bet on this with us. We have been watching what developers have built on Claude over the last few years, which made bringing our teams together an easy decision. The team gets to keep doing the work we love, on the platform where it matters most."