# Glossary

Common payment processing terms and definitions.

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## A

**ACH** - Automated Clearing House. Electronic network for financial transactions in the US.

**API Key** - Authentication credential for server-to-server API access, sent in the `x-api-key` header. Types: standard (`api-`), SDK public (`lpk_live_`), ERP / tenant-scoped (`lv_erp_`), processing (`lv_pk_`) and token processing (`ltk_`).

**Authorization** - Hold funds on a card without capturing them.

**AVS** - Address Verification Service. Verifies cardholder billing address.

**Approval** - A transaction the processor accepted. In the Public API: `Status: "1"`, `ResponseCode: "100"`.

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## B

**Batch** - Group of transactions settled together.

**Bearer Token** - Authentication token passed in API requests.

**Billing Cycle** - Period between recurring charges (`period`: Weekly, BiWeekly, SemiMonthly, Monthly, Quarterly, Annually or Custom).

**Branch / Location** - A child merchant of a parent merchant. The portal's "Locations & Devices" pages manage them.

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## C

**Capture** - Process an authorized transaction and transfer funds.

**Chargeback** - Customer disputes a charge with their bank. Tracked as a dispute in the Disputes API.

**Convenience Fee** - A surcharge added to a card payment when the merchant has fees enabled. Shown in `convenienceFee` on transactions and invoices.

**CVV** - Card Verification Value. 3-4 digit security code on cards.

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## D

**Decline** - Transaction rejected by card issuer or processor.

**Dunning** - Process of recovering failed recurring payments: automatic retries, then the subscription is paused (a dunning email is sent only when the merchant has failed-payment notices enabled).

**Dual Pricing** - Showing separate cash, card and ACH prices for the same sale (see Fee Preview).

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## E

**ECI** - E-commerce Indicator. 3DS transaction security level.

**ERP Key** - A tenant-scoped API key (`lv_erp_`) that acts for any merchant in the tenant; the merchant is chosen per request with `X-Merchant-ID`.

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## F

**Fraud Prevention** - Controls that block risky payments: AVS and CVV rules, per-gateway limits and WatchDog volume rules.

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## G

**Gateway** - Service that processes card transactions.

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## I

**Idempotency** - Ability to safely retry requests without duplicate processing, using the `Idempotency-Key` header on supported admin transaction endpoints.

**Invoice** - Bill sent to customer for payment.

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## M

**Merchant** - Business accepting payments.

**MCC** - Merchant Category Code. Business type classification.

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## P

**Payment Plan** - An installment schedule for a fixed total amount (billing service), as opposed to an open-ended subscription.

**PCI DSS** - Payment Card Industry Data Security Standard.

**pciToken** - Reference (`pci_tok_…`) to card data captured in the PCI-isolated hosted fields; send it instead of raw card numbers.

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## R

**Refund** - Return funds to customer. Refunds the processor declines go to the Refund Decline Queue and are retried only when a user triggers it.

**Retry** - Attempt failed operation again.

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## S

**Sandbox** - Test environment for development.

**Settlement** - Transfer of funds from processor to merchant.

**Subscription** - Recurring payment agreement (`/api/v1/recurring`).

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## T

**Tenant** - Isolated account in multi-tenant system.

**Token** - Secure reference to sensitive payment data.

**TPN** - Terminal Processor Number. The 12-digit, globally unique identifier of a device, paired with a pairing code during registration.

**Transaction** - Payment processing operation.

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## V

**Void** - Cancel transaction before settlement. Approved sales and authorizations can be voided; settled transactions must be refunded.

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## W

**WatchDog** - Per-merchant volume and count rules that block or reroute payments once a limit is reached.

**Webhook** - HTTP callback for real-time event notifications, signed with an HMAC-SHA256 header.

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