Paywall
A paywall is a method of restricting access to content via a paid subscription. 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. In academics, research papers are often subject to a paywall and are available via academic libraries that subscribe.
Paymentwall
Paymentwall is headquartered in San Francisco, with offices in Istanbul, Berlin, Kiev, Manila, Amsterdam, Las Vegas, Hanoi, Beijing, London, Lisbon, Seoul, Sofia, Poznan, Moscow and Novosibirsk.