Azerbaijani citizens can travel to Serbia without a visa. Under the bilateral instrument you may stay in the country for up to 90 days. A valid passport must be presented at the border crossing.
A rule on registering your place of stay applies; hotels handle this themselves, but if you stay in a private flat you must complete the registration yourself. Working and studying require a separate permit.
Belgrade is the main hub of the Balkan routes and can be combined with destinations such as Novi Sad and Zlatibor. Both direct and connecting flights are available from Baku. Viza.az compares direct and connecting flights and explains the registration requirement.