AWS CloudFormation vs cfn-lint

AWS CloudFormation models, provisions, and manages related AWS and third-party resources as infrastructure as code. YAML or JSON templates define AWS resources and their properties. StackSets deploy a common set of resources across multiple AWS accounts and Regions; Change Sets preview proposed stack updates, including possible deletion or replacement, and Drift Detection tracks changes made outside the service. For authoring, AWS CDK supports TypeScript, Python, Java, and .NET, while AWS SAM offers shorthand YAML for serverless resources that is converted during deployment. The CloudFormation Registry supports third-party resources and modules, and stacks can be updated from remote Git repositories. The service is available through API, Linux, macOS, web, and Windows, and manages state. CloudFormation itself has a free plan, with no additional charge for AWS and Alexa resource providers, but created AWS resources are billed at their standard rates. Third-party provider and custom hook operations may also incur charges. Access can be managed with IAM, and CloudTrail logs API calls.

cfn-lint is a free, open-source validator for AWS CloudFormation YAML and JSON templates. It checks templates against resource provider schemas and applies additional rules, including validation of property values and best practices. AWS Serverless Application Model templates are processed after transformation with AWS SAM. Users can configure built-in checks through command-line options, configuration files, or CloudFormation template metadata, and can add custom rules. Results can be emitted as quiet, parseable, JSON, JUnit, pretty, or SARIF output. Installation options documented by the project include pip, Homebrew for macOS, and Docker; supported Python versions are 3.10 through 3.14. Listed integrations include Atom, Emacs, NeoVim/Vim, Sublime, Visual Studio Code, IntelliJ IDEA, GitHub Actions, and pre-commit. The project treats complex template-value validation as best effort and does not fail merely because it cannot interpret or translate a value. The repository identifies its license as MIT No Attribution, and the plan costs nothing.