The EPP code, also known as an authorization or auth code, is a secret and unique set of characters assigned by the domain registrar.

This code is a safeguard that, along with other security measures (e.g., domain lock), guarantees that only the rightful owner can transfer a domain. If the wrong EPP code is provided when setting up a domain transfer, the transfer will not be completed.

The EPP key is required when transferring most TLDs, such as .COM, .NET, .ORG, .BIZ, .INFO, .US, etc.