In January 2017 Azerbaijan introduced electronic visas for citizens of 81 countries. The system is called ASAN. The visas are issued for a single-entry visit up to 30 days for a fee of $20.
The e-visa should be printed and presented together with your passport (which should be valid at least 3 months more than the validity period of the electronic visa) at the border checkpoint. Check the list of designated 81 countries on the official MFA website.
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Visa to Azerbaijan
More information
Get more details about the Azeri visa at the official Ministry of Foreign Affairs of Azerbaijan website.