What language are AWS CloudFormation templates written in?

AWS CloudFormation templates can be written in both JSON and YAML formats, making them flexible to work with depending on your preferences and use cases. While JSON was the original format provided for CloudFormation templates, YAML has become increasingly popular due to its readability and ease of use for defining complex configurations.

Choosing JSON means you can make use of its structured format to define your AWS resources, parameters, and outputs. JSON templates can be easily validated, and many developers are already familiar with it from using it in other contexts. However, one of the primary reasons many developers now also prefer YAML overrides the readability factor, as YAML uses indentation and a more concise syntax, making it easier to write and edit templates, especially for larger configurations.

In practice, both formats serve the same purpose and can define the exact same AWS resources, so choosing one over the other often comes down to personal preference and the requirements of the specific application or team. Therefore, while JSON is indeed one of the formats used in AWS CloudFormation, YAML has also emerged as a valid and popular alternative, which may make the provided response incomplete.