Are you using alf.io for selling tickets and/or collecting attendes for your event?
Then this app is for you! Download it and follow the instructions on the website (https://alf.io/docs/event-management/check-in/check-in-app/) in order to get ready to welcome your attendees!

You can also allow sponsors to collect attendees' data just by scanning the QR-Code on their badges, and therefore respecting attendees' privacy.