Check Verification is a process that screens checks and check writers against a "negative database" of "bad check writers". This is done at the point of sale when the customer presents a check as payment.

This service is performed using a point of sale terminal (or a real-time internet process) to access one of these large negative databases and compare the new transaction against the list. If the customer has a history of bad checks, the transaction will be declined. If they are not in the database for bounced checks, they are approved.