A blacklist is a tool used to block users or entities from accessing your services based on specific criteria — such as a history of fraud, excessive chargebacks, or suspicious behavior. Blacklists often include variables such as IP addresses, email domains, device IDs, and payment methods. When a new transaction matches a blacklist entry, it’s typically declined automatically or flagged for review. Blacklisting is a preventive method that reduces repeated abuse.

Maintaining an up-to-date blacklist helps you stop known threats before they result in repeated fraud or disputes. AltoPay supports rule-based blacklisting and lets you automatically block repeat offenders across multiple channels. Reviewing your blacklist regularly helps ensure you’re catching fraud patterns without impacting legitimate users. It’s also a valuable tool for managing region-specific fraud spikes or abuse campaigns.