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

Metadata assigned to an Amazon RDS resource consisting of a key-value pair.

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

**Note**  
In the following list, the required parameters are described first.

 ** Key **   <a name="performanceinsights-Type-Tag-Key"></a>
A key is the required name of the tag. The string value can be from 1 to 128 Unicode characters in length and can't be prefixed with `aws:` or `rds:`. The string can only contain only the set of Unicode letters, digits, white-space, '\$1', '.', ':', '/', '=', '\$1', '-', '@' (Java regex: `"^([\\p{L}\\p{Z}\\p{N}_.:/=+\\-@]*)$"`).  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Pattern: `^.*$`   
Required: Yes

 ** Value **   <a name="performanceinsights-Type-Tag-Value"></a>
A value is the optional value of the tag. The string value can be from 1 to 256 Unicode characters in length and can't be prefixed with `aws:` or `rds:`. The string can only contain only the set of Unicode letters, digits, white-space, '\$1', '.', ':', '/', '=', '\$1', '-', '@' (Java regex: "^([\$1\$1p\$1L\$1\$1\$1p\$1Z\$1\$1\$1p\$1N\$1\$1.:/=\$1\$1\$1-@]\$1)\$1").  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 256.  
Pattern: `^.*$`   
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/pi-2018-02-27/Tag) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/pi-2018-02-27/Tag) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/pi-2018-02-27/Tag)