The Coordination Center for TLD .RU/.РФ, together with the Поддерживаю.РФ (I Support .РФ) project, has released the results of its annual study on the level of support for internationalized email addresses (EAI) in Russia’s country-code top-level domains, .RU and .РФ.
The study evaluated support for the SMTPUTF8 extension of the SMTP protocol on mail servers specified in the MX records of second-level domain names in the .RU and .РФ domains. SMTPUTF8 enables mail servers to send and receive emails using addresses written in national scripts, including Cyrillic.
As of April 2026, 40,285 domain names in the .РФ domain had at least one MX record pointing to an active mail server supporting SMTPUTF8. In the .RU domain, the figure reached 486,535 domain names. The number of unique mail servers supporting the SMTPUTF8 extension also continued to grow. Compared with 2025, their number increased from 1,710 to 1,826 in the .РФ domain; and from 21,422 to 24,037 in .RU.
The study also identified shifts in the distribution of mail service providers. In 2026, the largest share of domain names pointing to servers supporting SMTPUTF8 was hosted by Reg.ru’s email service, accounting for 80 percent of such domains in .РФ and 41 percent in .RU. Open-source software continues to dominate the mail server market. Exim remains the most widely used mail transfer agent, with the number of unique servers advertising SMTPUTF8 support steadily increasing over the past three years: from 786 to 1,230 servers in .РФ and from 5,445 to 8,438 servers in .RU.
“The findings show that the infrastructure supporting internationalized email addresses continues to develop. The number of unique mail servers capable of sending and receiving messages using internationalized email addresses is growing every year. This demonstrates the wider adoption of the technology by email service providers and the increasing resilience of Russia’s internationalized email ecosystem," Head of Поддерживаю.РФ Maria Kolesnikova said.
The study has been carried out every year since 2024. This year’s report is based on data collected in April 2026.
The full text of the research is available on поддерживаю.рф.
