Tag

An object that defines the tags associated with an application. A tag is a label that you optionally define and associate with an application. Tags can help you categorize and manage resources in different ways, such as by purpose, owner, environment, or other criteria.

Each tag consists of a required tag key and an associated tag value, both of which you define. A tag key is a general label that acts as a category for a more specific tag value. A tag value acts as a descriptor within a tag key. A tag key can contain as many as 128 characters. A tag value can contain as many as 256 characters. The characters can be Unicode letters, digits, white space, or one of the following symbols: _ . : / = + -. The following additional restrictions apply to tags:

• Tag keys and values are case sensitive.

• For each associated resource, each tag key must be unique and it can have only one value.

• The aws: prefix is reserved for use by Amazon Web Services; you can’t use it in any tag keys or values that you define. In addition, you can't edit or remove tag keys or values that use this prefix.