Anthropic acquires Stainless, ending its hosted SDK tooling

Anthropic, the artificial intelligence company, has acquired the developer tools startup Stainless, a move that consolidates a key piece of infrastructure used widely across the AI industry under its exclusive control. The deal was announced on Monday, though financial terms were not disclosed. Prior reports indicated the acquisition price exceeded $300 million.

Stainless, founded in 2022 by former Stripe engineer Alex Rattray, built software that automates the creation and maintenance of software development kits (SDKs). Its platform converts API specifications into production-ready SDKs across multiple programming languages, including Python, TypeScript, Go, Java, and Kotlin, and automatically updates them when APIs change. This technology has been used by hundreds of companies, including major AI developers such as OpenAI, Google, Cloudflare, Replicate, and Runway.

Anthropic stated that Stainless has generated every official SDK for its Claude API since the API’s launch. Following the acquisition, Anthropic plans to shut down all hosted Stainless products, including its SDK generator platform. Existing customers will retain ownership and modification rights for SDKs they have...