# Validate your Amazon SAM applications with Amazon CloudFormation Linter
<a name="validate-cfn-lint"></a>

 Amazon CloudFormation Linter (cfn-lint) is an open-source tool that you can use to perform detailed validation on your Amazon CloudFormation templates. Cfn-lint contains rules that are guided by the Amazon CloudFormation resource specification. Use cfn-lint to compare your resources against those rules to receive detailed messages on errors, warnings, or informational suggestions. Alternatively, create your own custom rules to validate against. To learn more about cfn-lint, see [cfn-lint](https://github.com/aws-cloudformation/cfn-lint) in the *Amazon CloudFormation GitHub repository*. 

 You can use cfn-lint to validate your Amazon Serverless Application Model (Amazon SAM) templates through the Amazon SAM Command Line Interface (Amazon SAM CLI) by running **sam validate** with the **--lint** option. 

```
sam validate --lint
```

 To customize cfn-lint behavior, such as creating custom rules or specifying validation options, you can define a configuration file. To learn more, see [Config File](https://github.com/aws-cloudformation/cfn-lint#config-file) in the *cfn-lint Amazon CloudFormation GitHub repository*. When you run **sam validate --lint**, cfn-lint behavior defined in your configuration file will be applied. 

## Examples
<a name="validate-cfn-lint-examples"></a>

### Perform cfn-lint validation on an Amazon SAM template
<a name="validate-cfn-lint-examples-example1"></a>

```
sam validate --lint --template myTemplate.yaml
```

## Learn more
<a name="validate-cfn-lint-learn"></a>

 To learn more about the **sam validate** command, see [sam validate](sam-cli-command-reference-sam-validate.md).