SITE.su is an online marketplace for premium domain names, offering a catalogue of approximately 39,000 to 40,000 domains in the .ru, .su, and .рф extensions. Customers can browse and search for domains by keyword or use advanced search options to find names that suit a business, project, or personal brand. The site provides listings with purchase and monthly rental prices, along with information such as domain age and search-related indicators.

Domains can be purchased online, with administration rights transferred to the buyer, or rented through an arrangement that lets the customer assign their own DNS servers. Rental agreements include a priority right to purchase the domain at a price fixed in the contract, and may run for up to 50 months. The marketplace also offers downloadable domain lists in Excel format and invites visitors to ask questions or make an offer on a listing. Help, contacts, and online chat are available through its support section.