Cloudflare open-sources Forge, a pipeline that generates its own SDKs, CLIs and docs from OpenAPI on every pull request: Reveneau

Why it mattersAny team that publishes an API can now ship its client libraries, command line and docs from the same source in one CI job, and see what breaks before the merge instead of after it.

A published API has three shadows: the SDKs in every language, the command line that wraps them, and the docs a customer reads. Keep them in sync by hand and one always drifts. Cloudflare has released the pipeline it uses to keep its own in sync, and the code is free.

Cloudflare open-sourced Forge on 28 September 2026 under Apache 2.0. Forge is a generation pipeline that runs in a CI job and turns an API definition into SDKs, CLIs, API documentation, Cap'n Web specifications and Model Context Protocol servers. Cloudflare says the same pipeline already generates outputs for its own cf CLI and powers "over 3,500 API operations" across its infrastructure.

What it produces

Forge accepts OpenAPI as its input today, and Cloudflare says it plans to add AsyncAPI, GraphQL, Cap'n Proto and Protobuf. On the output side it generates SDKs for TypeScript, Rust, Python, Go and PHP, with Terraform planned. It writes API documentation next to the SDKs, and it writes MCP servers so an AI agent can call the API through the same definitions.

Each output is a plugin, called a transformer, and a team writes its own transformer when the built-in set does not cover something.

The bit that is new

Cloudflare's own claim for what makes Forge different is that transformers can be chained. The output of one is the input of the next: an SDK becomes the input to a CLI generator, and the CLI generator writes commands in whatever language the SDK is in. Cloudflare puts the practical case directly: a team can generate a Python CLI, or a TypeScript CLI, without accepting the language a single SDK generator happened to choose.

That matters because the standard SDK generators, the ones Cloudflare is quietly comparing against here, decide the language of the client for you. Forge does not. A team also writes handwritten commands into the same repo, and Forge documents those alongside the generated ones so the published docs cover the whole tool.

The CI story

The pipeline runs in each team's own API repository. On every pull request, Forge lints the change, generates a preview build, and highlights what changed so a reviewer can test the new SDK and CLI against the new definition before the code merges. Cloudflare frames this as catching a broken generator step at review time rather than at release time.

Two things to state plainly. First, every claim about how Forge performs comes from Cloudflare's own account of a project Cloudflare wrote for its own purposes, so treat "3,500 API operations" as a scale claim by the vendor rather than an independent audit. Second, chaining transformers is powerful, and a chain that generates a bad SDK will also generate a bad CLI and bad docs, so the discipline the CI pull-request check imposes is not optional in practice.

Still, the shape is the one that fits the way an API is actually built. The OpenAPI file is the source, and everything else is a derivation. A team that publishes an API and wants its client libraries, its command line and its documentation to stop drifting from each other has been reaching for OpenAPI Generator, Speakeasy, Stainless or a homegrown script for years. Forge is another option, and its price is zero. Cloudflare's stated position: "You should own your SDKs, CLIs, and docs."

Source

Cloudflare blog: Introducing Forge: the open source pipeline for generating SDKs, CLIs, docs, and more
Repository: cloudflare/forge on GitHub

This item was written by an AI system from the linked source. Reveneau is responsible for what it publishes.