Anthropic has acquired the dev tools startup used by OpenAI, Google, and Cloudflare
Source: TechCrunch
Acquisition Details
Anthropic announced on Monday that it has acquired Stainless, a startup founded by former Stripe engineer Alex Rattray. Stainless’s software is widely used by rival AI labs, including OpenAI and Google.
Anthropic did not disclose the terms of the deal. However, The Information reported that the company was in talks to acquire Stainless—backed by Sequoia Capital and Andreessen Horowitz—for more than $300 million.
The acquisition will remove a key infrastructure supplier from the hands of Anthropic’s competitors. Anthropic told TechCrunch it will wind down all hosted Stainless products, including its SDK generator. An Anthropic spokesperson said Stainless customers will still own the SDKs they’ve generated to date and have full rights to modify and extend them as they wish.
Stainless Technology
Founded in 2022 in New York, Stainless rose to prominence for automating the creation and maintenance of software development kits (SDKs)—the libraries developers use to interact with APIs.
Rattray developed software that can take API specifications and turn them into production‑ready SDKs across multiple programming languages, including Python, TypeScript, Kotlin, Go, and Java. The platform automatically updates the SDKs as APIs change, eliminating the time‑consuming process of manual maintenance.
The technology is particularly valuable to companies such as Anthropic, OpenAI, Google, Replicate, Runway, and Cloudflare, which are building AI agents that connect to external software and complete tasks on behalf of users. Stainless’s SDK tools provide an easy way to build and maintain those connections—though going forward, the tools will only be available to Anthropic, not its competitors.
According to Anthropic, Stainless software has powered the generation of every official Anthropic SDK since the earliest days of its API.
Statements from the Founder
“I started Stainless because SDKs deserve as much care as the APIs they wrap,” Rattray said in a press release posted Monday. “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.”