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

Describes a tag. A tag is a key-value pair. You can add up to 50 tags to a single Amazon Keyspaces resource.

 AWS-assigned tag names and values are automatically assigned the `aws:` prefix, which the user cannot assign. AWS-assigned tag names do not count towards the tag limit of 50. User-assigned tag names have the prefix `user:` in the Cost Allocation Report. You cannot backdate the application of a tag.

For more information, see [Adding tags and labels to Amazon Keyspaces resources](https://docs.aws.amazon.com/keyspaces/latest/devguide/tagging-keyspaces.html) in the *Amazon Keyspaces Developer Guide*.

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

 ** key **   <a name="keyspaces-Type-Tag-key"></a>
The key of the tag. Tag keys are case sensitive. Each Amazon Keyspaces resource can only have up to one tag with the same key. If you try to add an existing tag (same key), the existing tag value will be updated to the new value.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

 ** value **   <a name="keyspaces-Type-Tag-value"></a>
The value of the tag. Tag values are case-sensitive and can be null.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 256.  
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/keyspaces-2022-02-10/Tag) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/keyspaces-2022-02-10/Tag) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/keyspaces-2022-02-10/Tag)