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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 · 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, refund is the only way to return funds.

See also: DMS, Void

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.

D​

DMS​

Dual-message system. A two-stage payment flow:

  1. Authorization holds funds on the customer's card. Triggered by /api/v1/session against a DMS-enabled MID.
  2. 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.

See also: SMS, Capture, Void

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.

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.

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.

See also: Cascading, MID

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 triggered by the merchant using a previously stored card token. Differs from a one-off charge in its 3DS challenge behaviour and its MIT treatment. See Recurring.

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: true in the auth request to receive a card_token in the callback; reuse it via card_token: ["..."] on later requests. Often paired with Recurring. See Tokenization.

V​

Void​

Cancelling a DMS authorization before capture, releasing the held funds back to the card. Triggered by /api/v1/payment/void. After capture, use refund instead.

See also: DMS, Capture