What is a paywall?
Paywall
a method of restricting access to content via a paid subscription

A paywall is a method of restricting access to content via a paid subscription.[1][2] Beginning in the mid-2010s, newspapers started implementing paywalls on their websites as a way to increase revenue after years of decline in paid print readership and advertising revenue.[3] In academics, research papers are often subject to a paywall and are available via academic libraries that subscribe.[4][5]