M.ONL is an email mailbox service that lets customers create addresses on a range of domain names, including m.onl, d.onl, durcoin.ru, hotmail.ru, and others. The site presents mailbox setup as a four-step process: choose an address, select a plan, make a payment, and complete the order. Creation prices vary by the length of the chosen name, with separate rates for one-, two-, three-, four-, and five-or-more-character addresses. Customers can also extend an existing mailbox for one month or one year.

Payments are made in DURCOIN, with prices shown alongside approximate values in US dollars and a stated exchange rate. The service provides payment details for each order and requires customers to include an attachment, or memo, so the payment can be matched to the mailbox request. A d.onl wallet payment option is available, along with a feature to check payment status. The site supports multiple interface languages and directs users with questions or issues to its chat.