GlobalSignIn works together with partners in the travel industry to keep track of an updated database of visa requirements of many countries in the world. We are constantly updating our list of supported countries.
With GSI, it is thus possible to have an online registration form, where a registrant is asked for his/her nationality, and we will automatically on-the-spot notify the registrant whether he/she needs a visa to go to the event’s destination:

On your side, the event organizer side, you are then able to generate a report to list down all the people who need visa to go to the selected destination. This information is useful in that it can then be used to automatically generate Invitation Letters to be sent to respective embassies to grant your registrant his/her visa.