ETIAS (European Travel Information and Authorisation System) will require most visa-exempt travelers to obtain pre-travel authorisation before visiting the Schengen Area.
Like the US ESTA or the Canadian eTA, ETIAS is not a visa. It is a digital travel authorisation tied to your passport, valid for 3 years or until your passport expires.
ETIAS does not change the 90/180 rule — it is an additional security and pre-screening step. You will still need to comply with the Schengen stay limits.
Citizens of countries currently exempt from Schengen visas will be required to obtain ETIAS once the system launches. Check the official European Commission site for the current status.