A DNS domain name consists of a series of labels separated by dots. Each label can be up to 63 bytes long. The total length of a domain name cannot exceed 255 bytes including the dots. Route 53 supports any valid domain name.

You can use any ASCII character from 0 to 255 decimal, but you must use escape codes in the format \three-digit octal code to use any of the following characters:

For example, to create a hosted zone for the subdomain fübar under the domain example.com, you would specify f\374bar.example.com.

For a list of ASCII characters and the corresponding octal codes, do an Internet search on "ascii table".

You can include any of the following characters without using escape codes:

0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z ! " # $ % & ' ( ) * + , - / : ; < = > ? @ [ \ ] ^ _ ` { | } ~ .

For alphabetic characters, regardless of whether you specify upper-case letters, lower-case letters, or the corresponding letters in escape codes, Route 53 stores them internally as lower-case letters.

If the domain name includes any characters other than a to z, 0 to 9, - (hyphen), or _ (underscore), the Route 53 ListResourceRecordSets API action returns the characters as escape codes in the format \three-digit octal code. This is true whether you specified the characters as characters or as escape codes when you created the resource record set. The Route 53 console displays the characters as characters, not as escape codes.