Anthropic has acquired the dev tools startup used by OpenAI, Google, and Cloudflare

Anthropic has acquired the dev tools startup used by OpenAI, Google, and Cloudflare Kirsten Korosec 12:27 PM PDT · May 18, 2026 Anthropic announced Monday it has acquired Stainless, a startup founded by former Stripe engineer Alex Rattray whose software is widely used by rival AI labs, including OpenAI and Google. Anthropic didn’t disclose terms of the deal. However, The Information reported last week that Anthropic was in talks to acquire Stainless, which is backed by Sequoia Capital and Andreessen Horowitz, for more than $300 million. The acquisition will take a key infrastructure supplier out of the hands of Anthropic’s competitors. The company 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 however they wish. The New York-based startup, founded in 2022, rose to prominence in the emerging AI industry for automating the creation and maintenance of software development kits, or SDKs — the libraries developers use to interact with APIs. Rattray developed software that could take API specifications and turn them into production-ready SDKs across multiple programming languages, including Python, TypeScript, Kotlin, Go, and Java. It became a popular tool because the platform automatically updates the SDKs as APIs change and eliminated the time-consuming process of manually maintaining them. The technology is particularly valuable to companies like Anthropic, OpenAI, Google, Replicate, Runway, and Cloudflare that are building AI agents that can connect to external software and complete tasks on behalf of users. Stainless’s SDK tools are an easy way to build and maintain those connections — but 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. “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.” When you purchase through links in our articles, we may earn a small commission. This doesn’t affect our editorial independence. Kirsten Korosec Transportation Editor May 27 Athens, Greece StrictlyVC Athens is up next. Hear unfiltered insights straight from Europe’s tech leaders and connect with the people shaping what’s ahead. Lock in your spot before it’s gone. Most Popular Users turn to jailbreaking their older Kindles as Amazon ends support Lauren Forristal OpenAI launches ChatGPT for personal finance, will let you connect bank accounts Ivan Mehta US orders travelers on Air Force One to throw away gifts, pins, and burner phones after China trip Lorenzo Franceschi-Bicchierai OpenAI is reportedly preparing legal action against Apple; it wouldn’t be the first partner to feel burned Connie Loizos How to turn off Instagram’s new Instants feature and retract photos you accidentally shared Aisha Malik Spotify launches a Wrapped-style recap of your entire listening history Ivan Mehta Amazon launches 30-minute delivery across the US Sarah Perez X LinkedIn Facebook Instagram youTube Mastodon Threads Bluesky TechCrunchStaffContact UsAdvertiseCrunchboard JobsSite Map Terms of ServicePrivacy PolicyRSS Terms of UseCode of Conduct AnthropicSAPSamsungMarc LoreTechCrunch DisruptTech LayoffsChatGPT © 2026 TechCrunch Media LLC.