# TagRef
<a name="API_TagRef"></a>

Optional metadata that you apply to a resource to assist with categorization and organization. Each tag consists of a key and an optional 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_TagRef_Contents"></a>

 ** key **   <a name="appmesh-Type-TagRef-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  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

 ** value **   <a name="appmesh-Type-TagRef-value"></a>
The optional part of a key-value pair that make up a tag. A `value` acts as a descriptor within a tag category (key).  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 256.  
Required: Yes

## See Also
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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/appmesh-2019-01-25/TagRef) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/appmesh-2019-01-25/TagRef) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/appmesh-2019-01-25/TagRef)