Anthropic Acquires Stainless for Over 300 Million Dollars, Pulling a Key Tool Away From OpenAI and Google
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Anthropic has acquired Stainless, a New York-based startup founded in 2022 by former Stripe engineer Alex Rattray whose SDK generation software has been widely used across the AI industry, including by OpenAI, Google, Replicate, Runway, and Cloudflare. The Information reported the deal was valued at more than $300 million, though Anthropic did not disclose official terms. Stainless built software that takes API specifications and automatically generates production-ready software development kits across multiple programming languages including Python, TypeScript, Kotlin, Go, and Java, eliminating the time-consuming process of manually maintaining SDKs as APIs change. The technology became particularly valuable as AI companies raced to build agents capable of connecting to external software and completing tasks on behalf of users, making well-maintained SDKs a critical piece of infrastructure.The strategic significance of the acquisition goes beyond bringing useful technology in-house.
By acquiring Stainless and winding down all its hosted products including the SDK generator, Anthropic is effectively removing a key infrastructure supplier from its competitors. Companies that previously relied on Stainless to build and maintain their developer tooling will need to find alternatives, while Anthropic retains exclusive access to the team and technology going forward. Stainless customers who have already generated SDKs will retain full ownership and rights to modify them, but no new hosted services will be available to non-Anthropic clients. Anthropic noted that Stainless software has powered every official Anthropic SDK since the earliest days of its API, making the acquisition a formalization of a relationship that has been central to Anthropic's developer infrastructure from the beginning.