Anthropic has acquired Stainless and shut down its SDK generator, thenewstack.io reports. In response, Cloudflare has open-sourced its own SDK generation tool, Forge, according to the same outlet.
The report, published Monday, September 28, 2026, describes a direct sequence: Anthropic's purchase of Stainless was followed by the closure of the Stainless SDK generator, and Cloudflare then made Forge available as open source. Thenewstack.io frames Forge as the alternative to the tool Anthropic discontinued.
SDK generators produce software development kits that let developers call a company's APIs from their own code. The reporting does not detail Anthropic's reasons for the acquisition or the shutdown, nor does it specify a license or repository for Forge. Those specifics are not included in the available material.
What the report does establish is the outcome for developers who relied on Stainless: the generator is no longer operating, and Cloudflare's Forge is now offered under an open-source model. Thenewstack.io presents the two moves as connected events rather than separate announcements.
The story is notable for how quickly a closed tool was matched by an open alternative. Anthropic's acquisition removed a generator from the market, and Cloudflare's release put a comparable capability into open source, per thenewstack.io.
Watch for Cloudflare to publish Forge's license, repository and documentation, and for Anthropic to say what it intends to do with Stainless's technology.
