2 Comments on “What is the maximum key length of a tag?”

1. AWS Enthusiast says:

   August 19, 2017 at 10:12 am

   Key (127 characters maximum)
   Value (255 characters maximum)

   
   
   
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2. Don says:

   September 13, 2017 at 3:34 am

   Maximum key length: 128 Unicode characters
   Maximum value length: 256 Unicode characters
   Case sensitive
   Maximum number of tags per resource: 50
   Maximum active tag keys for Billing and Cost Management reports: 500
   Reserved prefix—aws:
   AWS-generated tag names and values are automatically assigned the aws: prefix, which you cannot assign. User-defined tag names have the prefix user: in the Cost Allocation Report.
   Use each key only once for each resource. If you attempt to use the same key twice on the same resource, your request will be rejected.
   You cannot tag a resource at the same time you create it. Tagging requires a separate action after the resource is created.
   You cannot backdate the application of a tag. This means that tags only start appearing on your cost allocation report after you apply them, and do not appear on earlier reports.
   Allowed characters are letters, whitespace, and numbers, plus the following special characters: + – = . _ : /
   Note
   If you need characters outside this allowed set, you can apply standard base-64 encoding to your tag.

   
   
   
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