Concepts and glossary
Definitions for the terms used throughout these docs. Each term has a deep-link anchor. For example, DMS jumps to the DMS definition. Larger concepts get a short summary here with a link to the full feature page.
Jump to: A · C · D · F · H · M · N · P · R · S · T · V
Letters that have no entries are omitted from the index.
A
ACS
Access control server. The issuer's server that hosts 3-D Secure authentication. During a 3DS challenge, the Checkout page redirects the customer to the ACS to authenticate with their bank; the ACS then redirects back to your site.
APM
Alternative payment method. A non-card payment method, such as PayPal, iDEAL, Sofort, bank transfers, wallets, and crypto on/off-ramps. See the S2S APM guide.
ARN
Acquirer reference number. Identifies a transaction in card-network reconciliation. Useful when investigating chargebacks with your acquirer.
C
Capture
The second stage of a DMS payment. Transfers funds that were previously held by an authorization, performed via /api/v1/payment/capture, scheduled auto-capture, or admin panel. After capture, return the funds with a refund, or with a void on the same financial day.
Card-on-File (COF)
A card saved during a customer payment so that later payments can use it without the card data. Payment Platform returns a card_token for the saved card and, where the acquirer supports it, registers the card with the acquirer as a stored credential. See Card-on-File payments.
See also: CIT, MIT, Tokenization
Cascading
Automatic retry of a payment across multiple MIDs or connectors when the first attempt is declined. Configured per merchant in admin panel → Custom routing.
See also: MID, Pre-routing
Channel ID
A logical identifier that routes a payment to a specific MID. Set on the auth request via channel_id. Surfaces in callbacks for traceability.
CIT
Customer-initiated transaction. A payment the customer triggered themselves (one-off checkout, manual top-up). Contrast with MIT. 3DS and SCA rules differ by initiation type. See Card-on-File payments.
Click to Pay
A Mastercard service that lets the customer pay with a card saved in their Click to Pay profile. Available on the Checkout payment page. See Click to Pay.
D
DMS
Dual-message system. A two-stage payment flow:
- Authorization holds funds on the customer's card. Triggered by
/api/v1/sessionagainst a DMS-enabled MID. - Capture transfers the held funds. Triggered by
/api/v1/payment/capture, scheduled auto-capture, or admin panel.
Used when capture should happen after a separate event, such as order shipment, marketplace settlement, or fulfilment confirmation. The authorization hold expires (typically 7 days; varies by issuer) if not captured. See DMS mode for the full flow.
DPAN
Digital primary account number. The card number a wallet (Apple Pay, Google Pay) presents at checkout. Distinct from the underlying FPAN, which stays at the issuer.
F
FPAN
Funding primary account number. The real card number behind a DPAN. Held at the issuer; never visible to the merchant.
H
HPP
Hosted payment page. A payment page rendered by the platform on its own domain; the merchant redirects the customer to it. The Checkout integration is HPP-style.
M
MID
Merchant identifier. Your account at a specific connector or acquirer. One merchant can have many MIDs (one per connector). Routing rules, DMS mode, and many other settings are configured per MID.
See also: Cascading, Pre-routing, Channel ID
MIT
Merchant-initiated transaction. A payment the merchant triggers, such as recurring charges, subscription billing, or account top-ups. Contrast with CIT. Required for recurring flows. See Card-on-File payments.
MOTO
Mail order / telephone order. A card payment the merchant takes on the customer's behalf from card details received by mail, email, or phone. It cannot go through 3DS. See MOTO payments.
MPI
Merchant plug-in. The software that runs 3-D Secure authentication and returns its result: ECI, authentication value, and Directory Server transaction ID. Payment Platform can run 3DS itself, or the merchant can authenticate the payer with its own MPI and send the result in mpi_data. See External 3DS.
N
Network token
A token issued by the card network (Visa, Mastercard) in place of the card number. The card network keeps it up to date when the card is reissued or expires. See Network tokens.
See also: Card-on-File, PAN
P
PAN
Primary account number. The card number printed on the front of the card. Subject to PCI-DSS handling rules; never stored unencrypted.
Pre-routing
Filtering of the payment methods shown on the Checkout page based on merchant rules: region, currency, BIN, and so on. Configured in admin panel → Custom routing. Bypassed when methods is explicitly set in the auth request. See Pre-routing for setup details.
Protocol mapping
The internal mapping between a merchant and a payment protocol (Checkout, S2S APM, S2S CARD, HPF). Set up during merchant onboarding by the platform team.
R
Recurring
A payment the merchant triggers with the recurring_token returned by an initial payment sent with recurring_init. It is an MIT. See Recurring payments and the Checkout Recurring request.
See also: MIT, Tokenization
RRN
Retrieval reference number. The acquirer's transaction identifier. Used in reconciliation, chargeback investigations, and acquirer support tickets.
S
SMS
Single-message system. A one-stage payment: authorization and capture happen together. The default mode for most MIDs. Contrast with DMS.
T
Tokenization
Storing a card so future charges can be made without the customer entering card details again. Send req_token=Y in S2S CARD or req_token: true in the Checkout Authentication request to receive a card_token, then send the card_token in later payments (in Checkout, as an array). See Card-on-File payments and Card data tokenization in Checkout.
V
Void
Cancelling a payment in settled status on the same financial day. Triggered by /api/v1/payment/void. A DMS authorization that was not captured is released with a refund instead: for a pending payment the refund is a reversal.