EAI (Email Address Internationalization)
Learn what Email Address Internationalization is, how it enables non-Latin email addresses, and how DMARCeye supports secure authentication.
What is EAI (Email Address Internationalization)?
EAI (Email Address Internationalization) is a standard that allows email addresses to include non-ASCII characters, such as accented letters, Cyrillic, Chinese, Arabic, or other scripts, in both the local part and the domain. This enables users around the world to use email addresses in their native languages, improving accessibility and cultural representation in digital communication.
Before EAI, email addresses were restricted to ASCII characters (A–Z, 0–9, and limited symbols), making them difficult to adapt for non-Latin languages. The EAI standard extends compatibility while maintaining interoperability through protocols such as SMTPUTF8 and Internationalized Domain Names (IDNs).
How EAI Works
EAI modifies traditional SMTP to support Unicode characters in email addresses. For example:
用户@例子.公司 (user@例子.公司)Here, both the local part (用户) and the domain (例子.公司) use non-Latin characters. EAI-enabled servers process these addresses using the SMTPUTF8 extension and convert domain names through IDN encoding for DNS resolution.
Challenges and Compatibility
While EAI expands inclusivity, not all mail servers, applications, or security systems fully support internationalized addresses. Common issues include:
- Legacy systems rejecting non-ASCII addresses
- Inconsistent display or rendering across mail clients
- Authentication failures in SPF, DKIM, or DMARC if domain encoding mismatches occur
For these reasons, EAI adoption has been gradual, with increasing support across major providers like Gmail, Outlook, and Yahoo.
EAI promotes global accessibility by allowing users to create and use email addresses in their native scripts. It improves digital inclusion, supports local languages, and helps organizations communicate authentically with diverse audiences. However, full interoperability still depends on universal SMTPUTF8 and IDN support.
EAI and DMARCeye
DMARCeye supports analysis of authentication results for internationalized email domains. By interpreting Unicode and IDN-encoded data correctly, the platform ensures accurate visibility into authentication activity across global communication networks.
This enables organizations to secure their international domains, detect spoofing in localized scripts, and maintain consistent DMARC protection across all character sets.
Sign up for a free trial of DMARCeye today and secure your email domain.
To learn more about DMARC and DMARC-related terms, explore the DMARCeye Glossary.