AWS Certificate Manager
User Guide (Version 1.0)

Tag Restrictions

The following basic restrictions apply to ACM Certificate tags:

  • The maximum number of tags per ACM Certificate is 50.

  • The maximum length of a tag key is 127 characters.

  • The maximum length of a tag value is 255 characters.

  • Tag keys and values are case sensitive.

  • The aws: prefix is reserved for AWS use; you cannot add, edit, or delete tags whose key begins with aws:. Tags that begin with aws: do not count against your tags-per-resource limit.

  • If you plan to use your tagging schema across multiple services and resources, remember that other services may have other restrictions for allowed characters. Refer to the documentation for that service.

  • ACM Certificate tags are not available for use in the AWS Management Console's Resource Groups and Tag Editor.