AWS CloudFormation supports both JSON and YAML for infrastructure-as-code templates. Converting from JSON to YAML produces smaller, more readable files that are easier to maintain, review in pull requests, and document with inline comments.

Convert CloudFormation JSON to YAML Online

For quick conversions, Format Pilot’s data formatter converts JSON to YAML instantly. Paste your CloudFormation JSON template, select JSON → YAML, and click Convert. The standard conversion handles all CloudFormation resource types and properties correctly. Copy the YAML output and validate it with the AWS CLI before deploying.

Using cfn-flip for CloudFormation-Specific Conversion

pip install cfn-flip
cfn-flip template.json template.yaml

cfn-flip is the AWS Labs tool specifically built for CloudFormation template conversion. It handles CloudFormation intrinsic function shorthand conversion — turning {"Fn::Sub": "string"} into !Sub "string" in YAML — which a general JSON-to-YAML converter does not do. Use cfn-flip when you want idiomatic CloudFormation YAML with shorthand tags.

Validate After Conversion

aws cloudformation validate-template --template-body file://template.yaml

Always validate the converted YAML before using it for deployments. The AWS CLI validates the template structure and checks that all resource types and property names are valid CloudFormation constructs.

Frequently Asked Questions

Does YAML work exactly the same as JSON in CloudFormation?

Yes — CloudFormation parses both formats before processing. The resource types, properties, conditions, and outputs behave identically. The only practical difference is that YAML supports comments (using #) and produces more readable files. Deployment behavior, stack outputs, and resource provisioning are unaffected by the template format.