SITE.su is an online marketplace specializing in premium domain names, with more than 40,000 listings across the .ru, .su, and .рф extensions. The service helps individuals and businesses find keyword-based domains for websites, brands, and other online projects. Customers can purchase a domain online with immediate transfer or rent one by assigning their own DNS servers. Rental options include a guaranteed right to buy, and visitors can contact the seller to ask questions or propose a price.

The marketplace provides tools to browse the full domain inventory, download a list for review, and search by keywords or other parameters. Listings show purchase and monthly rental prices, with additional information such as domain age and ratings available for some names. The site also groups suggestions by matching terms, transliterations, synonyms, and translations, helping users explore related options. Transactions, account access, inquiries, and customer assistance are handled through the website, which offers contact details and an online chat in its Help section.