Citizens of the most CIS countries do not need visa to enter Azerbaijan (except Turkmenistan).
Citizens of Turkey, Israel, Kuwait, Saudi Arabia, Oman, Bahrain, Qatar, Japan, South Korea, China, Malaysia and Singapore has simplified visa procedure. The visa is granted upon arrival at the Baku International Airport named after H.Aliyev. You need to fill in the Application form (provided at the airport), provide 2 passport photos and pay USD 10$ fee (for Turkish citizens), USD 40$ (for Israeli citizens) and USD 20$ for other citizens.
Citizens of other countries need to obtain visa before travelling to Azerbaijan.