# Tag


Describes a tag.

## Contents


 ** Key ** (request), ** key ** (response)  
The key of the tag.  
Constraints: Tag keys are case-sensitive and accept a maximum of 127 Unicode characters. May not begin with `aws:`.  
Type: String  
Required: No

 ** Value ** (request), ** value ** (response)  
The value of the tag.  
Constraints: Tag values are case-sensitive and accept a maximum of 256 Unicode characters.  
Type: String  
Required: No

## See Also


For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/ec2-2016-11-15/Tag) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ec2-2016-11-15/Tag) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ec2-2016-11-15/Tag)