# Blocklists

Use blocklists to prevent fraud and criminal activity.

Blocklists are lists of customer attribute values that are blocked from buying from you.
For example, if a customer attempts to make a purchase from you with a credit card that is in a blocklist, the transaction is blocked and is not processed.

Before a new transaction is processed in Rebilly, blocklists are examined to check for attributes related to the entity.
If a match is detected, the operation is aborted.
A blocklist that expires after a period of time is called a greylist.

- [GET /blocklists](/docs/dev-docs/api/blocklists/getblocklistcollection.md): Retrieves a list of all blocklists.
- [POST /blocklists](/docs/dev-docs/api/blocklists/postblocklist.md): Creates a blocklist.
- [GET /blocklists/{id}](/docs/dev-docs/api/blocklists/getblocklist.md): Retrieves a blocklist with a specified ID.
- [DELETE /blocklists/{id}](/docs/dev-docs/api/blocklists/deleteblocklist.md): Deletes a blocklist with a specified ID.