Infrastructure
MID (Merchant Identification Number)
Definition
MID (Merchant Identification Number) a unique identifier assigned to a merchant account, used to identify the merchant in card network transactions. The MID appears in transaction records and is used for routing, reporting, and dispute management. PayFac sub-merchants typically share their PayFac's MID rather than having their own. Having your own MID provides more control but requires direct underwriting.
Related Terms
Merchant Account
A bank account that enables a business to accept card payments. The merchant account holds funds from card transactions before settlement to the merchant's business bank account. Obtaining a merchant account requires underwriting by an acquirer. High-risk merchants face more scrutiny and may require specialized acquirers. Terms include processing limits, reserve requirements, and fee structures.
Acquirer
A bank or financial institution licensed by card networks to process card transactions on behalf of merchants. Also called acquiring bank or merchant acquirer. The acquirer provides the merchant account, assumes liability for merchant behavior, manages settlements, and handles chargebacks. Major acquirers include Worldpay, First Data (Fiserv), Chase Paymentech, and Elavon. Different acquirers have different risk appetites for merchant verticals.
TID (Terminal Identification Number)
A unique identifier for a specific payment terminal or point-of-sale device. Each physical terminal or virtual terminal has its own TID. A single MID can have multiple TIDs for different locations or channels. TIDs help with transaction routing, reporting, and terminal-specific configurations.
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