# Install cfn-format with Homebrew

Command-line tool for formatting AWS CloudFormation templates. Version 1.24.4 via Homebrew; verified 2026-07-25.

## Install

```sh
sudo av install brew:cfn-format
```

Additional install commands:

### macOS

- Homebrew (100%):

```sh
brew install cfn-format
```

  Evidence: local Homebrew formula metadata

## Package facts

- **Package key:** brew:cfn-format
- **Package manager:** Homebrew
- **Version:** 1.24.4
- **Source summary:** Command-line tool for formatting AWS CloudFormation templates
- **Homepage:** <https://github.com/aws-cloudformation/rain>
- **Repository:** <https://github.com/aws-cloudformation/rain>
- **Last updated:** 2026-07-25T14:20:49-04:00
- **Generated:** 2026-08-03T19:37:03+00:00

## Executables

- cfn-format (alias)

## Install behavior

- Bottle: not available

## Freshness

- Page generated: 2026-08-03
- Package-manager version: 1.24.4
## Project history and usage

cfn-format is the Homebrew-packaged command built from the AWS CloudFormation rain repository's `cmd/cfn-format`, focused on checking and formatting AWS CloudFormation templates.

### Project history

The upstream rain repository was created in 2019 and describes rain as a development workflow tool for AWS CloudFormation templates and stacks. Its README lists consistent formatting of CloudFormation templates as a key feature of `rain fmt`, including JSON/YAML conversion and YAML comment preservation.

### Adoption history

Homebrew packages `cfn-format` separately from rain, building the `./cmd/cfn-format` target from the rain source repository. This gives package users a narrower formatter binary without installing the broader rain workflow CLI name.

### How it is used

The Homebrew formula test runs `cfn-format -v test.template` and expects a formatted-ok message. The rain README documents the broader formatter behavior under `rain fmt`.

### Why package nerds care

cfn-format is package-nerd-interesting because it exposes one subcommand-sized slice of a larger CloudFormation workflow tool as its own formula, the kind of tiny binary split that helps scripts depend on exactly the formatter they need.

### Timeline

- 2019: rain GitHub repository metadata records public repository creation.
- 2019: GitHub release metadata records rain v0.1.0.
- 2026: Homebrew formula builds cfn-format from rain v1.24.4.

### Related projects

- rain is the upstream project and broader CloudFormation workflow CLI.
- cfn-flip is the older AWS Labs converter whose CLI usage now points users to `rain fmt`.

### Sources

- <https://api.github.com/repos/aws-cloudformation/rain>
- <https://github.com/aws-cloudformation/rain>
- <https://aws-cloudformation.github.io/rain/rain_fmt.html>
- <https://github.com/aws-cloudformation/rain#readme>
- <https://formulae.brew.sh/api/formula/cfn-format.json>


## Security Notes

infrastructure mutation or orchestration signal.

- **Geiger risk:** orange / medium
- infrastructure mutation or orchestration signal


## Combined YAML source

View the package source record on GitHub. [combined/cfn-format.yml](https://github.com/mxcl/pkgdb/blob/main/combined/cfn-format.yml)


## Sources

- pkg.so package database
- Geiger risk classifier
- curated package history
- pkgdb category and tag curation
- cross-ecosystem install command graph