An Auth-Code,[1][2] also known as an EPP code, authorization code, transfer code,[3] or Auth-Info Code,[1] is a generated passcode required to transfer an Internet domain name between domain registrars; the code is intended to indicate that the domain name owner has authorized the transfer.[2]
Auth-Codes are created by the current registrar of the domain. The registrar is required to provide the Auth-Code to the domain name owner within five calendar days of the owner's request, and ICANN accepts complaints about registrars that do not. Some registrars allow Auth-Codes to be generated by the domain owners through the registrar's website. All Generic top-level domains use an Auth-Code in their transfer process.[1]
The .nz domain registry used an eight-character Auth-Code called Unique Domain Authentication Identifier (UDAI) for domain transfers and name conflict procedures. The UDAI was provided to the domain owner by the domain's current registrar, and expired after 30 days.[4][5] With the .nz registry update in 2022 the term UDAI was retired, and the passcode is now also referred to as an Auth-Code.[6]