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Glossary/Merchant ID (MID)

Merchant ID (MID)

A unique identifier assigned to a business for payment processing purposes.

What is Merchant ID (MID)?

A Merchant ID (MID) is a unique identifier assigned to your business by your payment processor or acquiring bank. It's used to route transactions, track processing activity, and deposit funds to the correct account. Your MID is required when setting up terminals, integrating payment systems, and communicating with processor support. Large businesses with multiple locations may have multiple MIDs, or use one MID with multiple Terminal IDs (TIDs) for each location.

Why It Matters

Your MID is your identity in the payment processing world. You'll need it for hardware setup, software integration, and troubleshooting. Keep it secure—in the wrong hands, it could be used to route transactions improperly. When evaluating statements or disputing fees, your MID is the primary reference point.

Frequently Asked Questions

Your MID appears on your merchant agreement, processing statements, and terminal receipts. You can also get it from your processor's support team or merchant portal.

Yes. Multiple locations or different business lines often have separate MIDs for tracking and reporting. Some merchants use multiple MIDs for risk distribution.

MID identifies your merchant account. TID (Terminal ID) identifies a specific terminal or register within that account. One MID can have many TIDs.

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