Pay-by-Link is a payment method that lets a merchant send a customer a secure URL to complete a transaction online. The link usually opens a hosted checkout page where the buyer enters card or wallet details, so the merchant does not need to expose a full payment terminal or type out payment information in chat or email.
In cyber security, the main issue is trust in the link itself. Attackers can abuse pay-by-link flows with phishing, invoice fraud, or link substitution, tricking victims into paying the wrong recipient or entering data on a fake page. Defenders reduce this risk by using signed or expiring links, verifying the payment amount and merchant name, and sending links only through controlled channels. For businesses, pay-by-link is useful for remote collection, but it should be treated as a payment control, not just a convenience feature.