# Tag
<a name="API_Tag"></a>

The metadata to apply to a resource to help you categorize and organize them. Each tag consists of a key and a value, both of which you define. Tag keys can have a maximum character length of 128 characters, and tag values can have a maximum length of 256 characters.

## Contents
<a name="API_Tag_Contents"></a>

 ** Key **   <a name="ECR-Type-Tag-Key"></a>
One part of a key-value pair that make up a tag. A `key` is a general label that acts like a category for more specific tag values.  
Type: String  
Required: Yes

 ** Value **   <a name="ECR-Type-Tag-Value"></a>
A `value` acts as a descriptor within a tag category (key).  
Type: String  
Required: Yes

## See Also
<a name="API_Tag_SeeAlso"></a>

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/ecr-2015-09-21/Tag) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/ecr-2015-09-21/Tag) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/ecr-2015-09-21/Tag)