Within 11 days of Google announcing a partnership with Speakeasy to open-source an SDK code-generation suite, Cloudflare unveiled Forge, its own open-source tool for automatically generating SDKs, command-line interfaces, documentation and other tooling from API definitions. Both companies had been customers of Stainless, the SDK generator that Anthropic acquired and subsequently shut down.
Forge is distributed under an Apache 2.0 license and can be run, modified and deployed on private infrastructure without cost. In a blog post by Dimitri Mitropoulos, Matt Taylor and Samuel MacLeod, Cloudflare described the project as still in early stages. The tool currently generates output for Cloudflare's cf CLI, a unified command-line interface for the Cloudflare platform, with API documentation and SDKs scheduled to transition over in coming months.
We believe that building tools for APIs is a core part of the Internet, and you should be able to do that without needing a SaaS product.
Cloudflare blog post authors
The Stainless shutdown and its ripple effects
Google's announcement on September 17 revealed that it had lost its SDK-generation service when the provider was acquired and "abruptly announced its shutdown." The timing was particularly problematic, as Google was preparing to launch a new API.
This sudden disruption highlighted that proprietary, closed-source generators create unacceptable platform risk. If the industry relies on OpenAPI to define interfaces, the tooling to compile those interfaces into client libraries, CLIs, and agent tools should be open infrastructure.
The provider in question was Stainless. On May 18, Anthropic completed its acquisition of the SDK and MCP tooling company, after which Stainless announced plans to wind down its products, including the SDK generator. The closure affected numerous customers, including OpenAI, Google and Cloudflare. While these companies retained the SDKs that Stainless had already generated, they lost access to the shared service needed to regenerate and update those SDKs as their APIs changed.
Why Cloudflare built its own solution
Cloudflare had already begun developing components that would eventually become Forge. In April, the company released a technical preview of cf, a new unified command-line interface designed to expose Cloudflare's products through consistent commands for developers and AI agents. At that time, Cloudflare had created a new TypeScript-based schema and generation system to maintain synchronization between CLI commands, configuration, bindings and other interfaces with its API.
The initial preview was limited in scope, covering only a small subset of Cloudflare products, though the company indicated it was testing a version spanning its entire API surface. Forge represents the code-generation system that emerged from this work and now powers the output required by cf.
Cloudflare's dissatisfaction with hosted generation services stemmed from several factors. The company now maintains more than 3,500 API operations supported by hundreds of services managed by different engineering teams. A generator must accurately reflect changes across this sprawling API landscape in the tools customers use, without transforming every update into a company-wide coordination effort.
Additionally, Cloudflare wanted engineers to preview how API changes would affect generated SDKs, CLI tools and documentation before code was merged. The company also sought a system extending beyond conventional SDKs to include MCP servers and Cap'n Web bindings, which enable applications to invoke remote services through Cloudflare's TypeScript-based RPC system as if calling local functions.
External services proved inadequate for these requirements. Issues introduced in one part of Cloudflare's API could only surface when another team attempted a release, forcing engineers to trace failures through systems outside their control and coordinate fixes across company and vendor boundaries.
We've tried several hosted products that attempt to solve this, and relied on some in production. None of them solved this problem for us, and some have shut down entirely.
Cloudflare blog post authors
The open-source rationale
Cloudflare's decision to open-source Forge reflects lessons learned from Stainless's closure. Stainless's generator was proprietary and delivered as a hosted service, creating customer dependency on continued operation. Forge's permissive Apache 2.0 license allows developers to run it on their own infrastructure, modify it or fork the project for independent use.
AI agents amplify the importance of this approach. These systems increasingly rely on SDKs, CLIs and API bindings to understand software capabilities and interaction methods. When these interfaces lag behind underlying services, agents may operate from incomplete or outdated descriptions of functionality.
Cloudflare CTO Dane Knecht emphasized this concern when discussing why maintaining current interfaces has become more critical. "APIs have always been how software connects, but AI agents make the quality of SDKs, CLIs, and API bindings even more important," Knecht said in an email to The New Stack. "If that layer is stale or incomplete, an agent doesn't just have a worse developer experience, it can misunderstand what a service can do."
Cloudflare developed Forge because SDK and CLI generation has "become too important" to remain outside its internal development process. "Cloudflare needed a pipeline our teams could run, test, and extend themselves, and we think other developers should have access to that same kind of open, vendor independent foundation," Knecht added.
Current status and future work
Forge remains in early stages with substantial work ahead. cf represents its first production output, and Cloudflare plans to migrate API documentation and existing SDKs during coming months. Several input formats and generation targets discussed are also designated as future work.
The timing carries significance: within 11 days, Google and Cloudflare—both former Stainless customers—publicly committed to open-source SDK-generation infrastructure following the disappearance of the proprietary service they had depended on. Google characterized such dependency as an "unacceptable platform risk." Cloudflare, through Forge, is now working to eliminate the same risk from its own technology stack.