Cloudflare on September 28, 2026 introduced Forge, an open source generation pipeline for producing SDKs, command-line interfaces, documentation and other libraries from API specifications. The company said Forge is pluggable, released under the Apache 2.0 license, and free for anyone to deploy and run.
What Cloudflare announced
Cloudflare described Forge as "an open source, pluggable generation pipeline that anyone can deploy and run for free." The company said the project is early in its life but already generates the output required for its cf CLI, and that over the next few months it will power Cloudflare's API documentation, SDKs "and much more."
According to the post, Cloudflare built Forge for its own needs "in order to treat agents as our customers," and is open sourcing it because it believes everyone should be able to generate the surfaces agents need. CLIs, API SDKs, MCP servers and accompanying docs used to be needed only by developer products, the company said, but are now "table stakes for every product."
Why Cloudflare says it built its own
Cloudflare said its API has over 3,500 operations, and that the hundreds of services behind those APIs are written in many languages, including Rust, Go, TypeScript and Python. Building a CLI for the entire API, along with SDKs and API docs, required a code generation pipeline that could handle that scale across languages and team workflows, the company said.
The company said it had tried several hosted products aimed at the problem and relied on some in production, but that none solved it and "some have shut down entirely." Cloudflare said one team would merge a change that inadvertently broke the generation pipeline and another team would discover it at release time.
Forge instead runs in CI on each team's API repositories, lints every change, and generates preview builds of the CLI, docs and SDKs with only the author's changes highlighted, according to the post. Cloudflare compared the model to Workers Previews, applied to SDK generation across hundreds of services and repositories.
Transformers, chaining and input formats
Cloudflare said Forge transformers can generate more than conventional language targets. The company said Forge makes it possible to take an OpenAPI spec and generate Cap'n Web, its RPC system that lets TypeScript call a remote API as if it were a local method, opening the door to generating bindings from Workers to other APIs.
The post cited other possible targets, including TanStack Query bindings, Zod or Valibot schemas and MCP servers. Forge supports OpenAPI as an input type today, Cloudflare said, but is designed to allow AsyncAPI, GraphQL, Cap'n Proto, Protobuf or other formats in future.
Cloudflare said Forge lets users control target chaining themselves — producing one output from another — which it said matters because its own cf CLI is written in TypeScript and includes hand-written, local-only commands such as cf dev and cf build that need to be documented alongside generated output.
API versioning and what comes next
Cloudflare said its v4 API has been the one major version of its API for 10 years, while several operations carry internal 'v2' tags or 'beta' identifiers that have outlived that part of the product's lifecycle. The company said a big new v5 would leave many customers behind, and that it is working on an API versioning approach that allows new major versions without breaking old clients or SDKs.
The company said it will have more to share soon on SDKs for TypeScript, Rust, Python, Go, PHP and Terraform, adding that it will put "extra special care" into the Terraform transition.
What to do
- Teams that generate client libraries can deploy and run Forge themselves at no cost under the Apache 2.0 license, including privately and with custom modifications.
- Run Forge in CI on API repositories so changes are linted and preview builds of CLIs, SDKs and docs are produced per pull request, catching generation breakages before release.
- If your inputs are not OpenAPI, note that Cloudflare says only OpenAPI is supported today, with other formats planned.
- Cloudflare invites external contributions to the project.
Key facts and where they come from
- Forge is open source under the Apache 2.0 license and free to run privately with modifications.
we’re making Forge available open source under the permissive Apache 2.0 license
- Cloudflare's API has more than 3,500 operations.
Cloudflare’s API has over 3,500 operations
- Forge already generates output for the cf CLI.
already generates the output required for the cf CLI
- Forge runs in CI, lints changes and produces preview builds per pull request.
It lints every change, and then generates preview builds of the CLI, docs, and SDKs with just your changes highlighted that you can install to test.
- OpenAPI is the only supported input type today.
Forge supports OpenAPI as an input type today, but we’ve designed it to allow AsyncAPI, GraphQL, Cap‘n Proto, Protobuf, or other input formats in the future.
- Forge can generate Cap'n Web from an OpenAPI spec.
Forge makes it possible to take an OpenAPI spec and generate Cap’n Web directly.
- Cloudflare plans an API versioning approach that avoids breaking old clients.
we’re working on an API versioning approach that allows us to release new major API versions without breaking old clients or SDKs