Anthropic has acquired the dev tools startup used by OpenAI, Google
Anthropic announced Monday it has acquired Stainless, a dev tools startup whose SDK automation software is widely used by rivals like OpenAI, Google, and Cloudflare. This strategic acquisition will see Anthropic wind down Stainless's hosted products, granting it exclusive access to critical technology for building AI agents and impacting competitors.

Anthropic, a leading artificial intelligence research company, announced Monday it has acquired Stainless, a burgeoning dev tools startup whose software is widely leveraged by some of Anthropic's biggest rivals, including OpenAI, Google, and Cloudflare. This strategic acquisition removes a critical infrastructure supplier from the broader AI ecosystem, signaling a significant shift in the competitive landscape for companies building advanced AI agents.
While the terms of the deal were not disclosed by Anthropic, reports last week from The Information suggested the acquisition could exceed $300 million for the New York-based firm. Stainless had attracted notable venture capital backing from prominent firms such as Sequoia Capital and Andreessen Horowitz, underscoring the perceived value of its technology.
The immediate consequence of this acquisition is Anthropic's plan to discontinue all hosted Stainless products, notably its SDK generator. An Anthropic spokesperson confirmed that existing Stainless customers will retain full ownership and modification rights over SDKs they have already generated.
However, the future development and new generation of these vital developer tools will now be exclusively available to Anthropic. This move effectively takes a key resource out of the hands of its competitors, granting Anthropic a proprietary edge in accelerating its own agent development.
Founded in 2022 by former Stripe engineer Alex Rattray, Stainless quickly gained prominence for its innovative software that automates the creation and maintenance of Software Development Kits (SDKs). SDKs are essential libraries that enable developers to interact seamlessly with Application Programming Interfaces (APIs).
Stainless’s platform streamlines this often time-consuming process by converting API specifications into production-ready SDKs across multiple programming languages, including Python, TypeScript, Kotlin, Go, and Java. Crucially, the system automatically updates these SDKs as underlying APIs evolve, eliminating the need for manual upkeep.
This technology holds immense value for companies operating at the forefront of AI, such as Anthropic, OpenAI, Google, Replicate, Runway, and Cloudflare. These firms are actively developing AI agents designed to connect with external software and execute tasks on behalf of users.
Stainless's SDK tools provide an efficient and reliable method for building and maintaining these complex connections. Anthropic itself confirmed that Stainless software has been instrumental in generating every official Anthropic SDK since the earliest days of its API, highlighting its deep integration and importance to the company's own development.
Stainless founder Alex Rattray expressed enthusiasm about the merger, stating, "I started Stainless because SDKs deserve as much care as the APIs they wrap." He highlighted Anthropic as an early adopter and a team whose vision aligned with Stainless, making the integration a natural fit for both entities. Rattray emphasized the opportunity for his team to continue their work on a platform where it can have the most significant impact.
FAQ
Q: What is Stainless, and why is its acquisition by Anthropic significant?
A: Stainless is a New York-based startup founded in 2022 that developed software to automate the creation and maintenance of Software Development Kits (SDKs), which are crucial for developers to interact with APIs. Its acquisition by Anthropic is significant because Stainless's tools were widely used by many of Anthropic's competitors, including OpenAI and Google, and Anthropic plans to wind down hosted Stainless products, making future access exclusive to its own operations.
Q: How will this acquisition impact Anthropic's competitors who previously used Stainless?
A: Competitors, such as OpenAI, Google, and Cloudflare, will no longer have access to Stainless's hosted products and SDK generator for new development. While they retain ownership and modification rights over SDKs generated prior to the acquisition, the proprietary tools and future updates from Stainless will now be exclusively available to Anthropic, potentially slowing down their own agent development efforts that relied on Stainless.
Q: What happens to existing customers of Stainless?
A: Anthropic has stated that existing Stainless customers will still own the SDKs they have generated to date. They will also have full rights to modify and extend these previously generated SDKs as they wish. However, all hosted Stainless products, including the SDK generator, will be wound down, meaning new SDK generation or continued service for others from Stainless will cease.
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