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

A list of key/value pairs that identify an index, FAQ, or data source. Tag keys and values can consist of Unicode letters, digits, white space, and any of the following symbols: \$1 . : / = \$1 - @.

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

 ** key **   <a name="qbusiness-Type-Tag-key"></a>
 The key for the tag. Keys are not case sensitive and must be unique for the Amazon Q Business application or data source.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

 ** value **   <a name="qbusiness-Type-Tag-value"></a>
The value associated with the tag. The value may be an empty string but it can't be null.  
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/qbusiness-2023-11-27/Tag) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/qbusiness-2023-11-27/Tag) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/qbusiness-2023-11-27/Tag)