Internationalization Domain Names (IDN)

Mailgun's Messages API supports sending to addresses that use internationalized domain names in the to and from fields. When necessary, Mailgun will automatically convert the domains to the ADCII equivalent using Punycode.


Currently, sending domains cannot be created using non-ASCII characters.

Internationalized Email Addresses (SMTPUTF8) Mailgun supports internationalized email addresses though the use of the SMTPYTF8 extension. An Internationalized email address will contain a non-ASCII character in the local-part portion of the email address and may also use an internationalized domain name.

Mailgun supports internationalized email addresses in the following portions of our product:

  • Outgoing Messages (HTTP API)
  • Email Verification
  • Suppressions Lists

Match\recipient and forward action are supported for domains using international characters / punycode. However, sending to a punycode domain is not supported.

To send messages to an internationalized email address, the receiving mailbox provider must support the SMTPUTF8 extension