What Is a CAID Number? Card Acceptor ID Explained
A CAID (Card Acceptor ID) is an alphanumeric code your acquirer assigns, 1 to 15 characters long. It identifies where a transaction happened, a store, a terminal, or a checkout page. Your Merchant ID is a different number that names your business as a whole.
I've assembled representment evidence for disputes on my own stores. The reason code decided everything about what I sent. The CAID travels with a transaction into that evidence packet. Merchants who don't know where to find it lose time they don't have when a dispute deadline is running.
Key takeaways
- A CAID identifies where a transaction happened, down to the store or checkout page.
- Expect 1 to 15 alphanumeric characters, nearly 2x the usual 8-character TID.
- Check your settlement report first, since 75% have no self-serve lookup.
- One merchant account can hold many CAIDs, one per store or terminal.
- Include your CAID in the evidence you send when disputing a chargeback.
What is a CAID number?
A CAID (Card Acceptor ID) is the code an acquirer assigns to one transaction origin point, typically 1 to 15 alphanumeric characters. That origin point is a store, a terminal, or a checkout page. The code answers where a payment happened.
Other numbers on the transaction cover who the merchant is and which device took the charge.
A card network has to trace each transaction back to its exact origin, down to the store or checkout page. So the acquirer writes the CAID into the transaction message itself.
Ixopay puts the format at "alphanumeric values 1 - 15 characters long and unique to a particular transaction origin point."
One merchant account can hold many CAIDs. A business with several storefronts and a website usually has one per site, all under a single Merchant ID. So ask your acquirer for "our CAID" and you'll get a question back about which location you mean.
This is the part that catches merchants out on a form. A field labelled "CAID" wants the code for one acceptance point. Cover only the checkout you entered, and disputes from your other locations keep arriving untouched.
What is a CAID number used for?
A CAID lets acquirers, card networks, and merchants trace a transaction back to the exact terminal or checkout page it came from. That matters for fraud checks, reconciliation, and disputes. All three start with where a charge came from.
The code gets attached at the point of sale and travels with the charge from there. Authorization, settlement, and dispute records all keep it.
So a reviewer can pinpoint where a charge happened months later, without calling you to ask.
That lands differently for each party reading the transaction. Your acquirer uses the CAID to route settlement money to the right acceptance point. A card network uses it to spot a pattern at one location. That's how one bad terminal gets flagged before the others do.
You use it to tell two of your own storefronts apart, in a report where the Merchant ID is identical on every row.
A CAID answers only that one question, so a reviewer holding one still needs three other records:
- The transaction reference number finds the specific charge.
- The Merchant ID places the account it belongs to.
- The card record shows how the customer paid.
Where to find your CAID
Your CAID is printed on your settlement report, listed in your processor's portal, and available from your acquirer on request. On a platform-managed processor, support is the only route.
Acquirers assign the code at setup and store it in the systems that build those files and views. So the number is usually already in a document you have.
Work through the three in order:
- Settlement and batch reports. Find the batch summary, where acquirers print the acceptor identifiers next to the totals.
- Your processor's merchant portal. Look under account settings, terminal settings, or that store's location detail page.
- Your acquiring bank or platform support. Ask for the acceptor ID for one named location, with a recent transaction date.
Suppose you're on Shopify Payments or another platform-managed processor. The dashboard won't show it, so you have to ask the platform's support team.
That wait costs you days when an enrollment form is half-finished and the deadline is close.
A brand-new store may have no CAID until its first settlement cycle closes.
CAID vs. MID vs. BIN vs. TID
The CAID names the origin point, the MID names your business, the BIN names the issuing bank, and the TID names the device. One payment message carries all four. They split by what each one points at:
Only one of the four has a self-serve lookup. Reading your BIN off a card number tells you which bank you're dealing with on a dispute.
Our free BIN lookup tool resolves a card's issuing bank in seconds. That's the identifier most merchants need next.
CAID vs. Merchant ID (MID)
A CAID names the place a transaction came from and a MID names the business that owns the account, so one MID sits above many CAIDs. Ixopay puts the split plainly. A card acceptor ID "identifies the location of a transaction, while a merchant ID identifies the merchant to whom the transaction is attached."
Support teams ask for your Merchant ID first on almost any call, so keep that one somewhere you can reach.
Confusing the two was the identifier mistake I saw most often. Someone reads a form asking for a card acceptor ID and types in the MID instead, because that's the number they recognize. The enrollment then matches nothing. The form takes the digits, so nothing looks broken until the alerts never arrive.
CAID vs. Terminal ID (TID)
A CAID identifies the acceptance point a transaction ran through and a TID identifies the individual card reader that took it, so one CAID can cover several TIDs. Razorpay defines a terminal ID as "a unique identifier assigned to each payment terminal or POS device," and puts the length at "usually 8 characters."
The distinction only matters in physical retail. A store with four card readers has four terminal IDs and often one CAID over all of them. So a report split by TID tells you which register took a charge, and the CAID tells you which store.
Online there's no physical device, so the TID is absent or a stand-in your processor generates.
How does a CAID tie into chargeback disputes?
The CAID is part of the transaction record you submit as evidence when you dispute a chargeback, and it confirms where the disputed charge happened. A reviewer uses it to check your account of events against that record.
When you respond to a chargeback, you have to tie the disputed charge to a verifiable acceptance point. The CAID does that job alongside the reason code the issuer filed under and the transaction reference number. A reviewer can then confirm the charge you're defending is the one the cardholder disputed.
Our walkthrough of the chargeback process covers where that response sits in the wider sequence.
The number also matters before a dispute reaches you. Enrolling in chargeback alerts takes your BIN and your CAID together, and first-time merchants often get that pair wrong.
A wrong CAID there fails quietly. The enrollment saves, the dashboard looks healthy, and you find out weeks later when a chargeback lands that an alert should have caught. So check the code against a settlement file at enrollment, not after the first dispute.
A correct CAID on file is one supporting identifier. Your response still has to rebut the reason code the issuer filed under, which means matching your evidence to the documents that code asks for. A packet with perfect identifiers and the wrong argument loses.
So the practical case for knowing your CAID stays narrow. It clears an enrollment form and closes one gap in a dispute response.
FAQ
What does CAID stand for?
CAID stands for Card Acceptor ID, also written as card acceptor identification code. Acquirers and card networks use the term for the code naming where a transaction originated.
Is a CAID the same as a routing number?
No. A routing number identifies a bank for transfers between accounts, while a CAID identifies the merchant acceptance point a card transaction came from.
Can a CAID be reused across multiple businesses?
No. Each CAID is unique to one transaction origin point under one merchant account, so two separate businesses never share one.
What if I enter the wrong CAID on an enrollment form?
Nothing in the form tends to flag the error, so verify the number against a settlement file before you submit it. Your acquirer can confirm it against the location on file.
