Basic concepts (15 articles)
Definitions, differences and the underlying logic of virtual cards, USDT cards and payment terminology
Glossary entrance
Covers card types, card elements, authorization & clearing, authentication & security, tokenization, data security, fraud risk, disputes & chargebacks and compliant cross-border topics. Looking for a concept? Jump into the matching category article; this category and the foundation guide in the tutorial centercomplement each other — this is "concepts & principles", that is "step-by-step operation".
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U cards: definition and differences from virtual credit cards
U card is an informal industry term, not a card-network category. Distinguish funding source, card form and prepaid attributes across deposit and payment flows.
Card types and forms: physical, virtual and single-use cards
Physical, virtual and single-use cards describe form and lifespan, not credit, debit or prepaid funding. Compare acceptance, recurring use and security risks.
Card details: PAN, BIN, expiry and CVV
PAN, BIN, expiry, CVV and dynamic security codes serve different checks. Review their use and storage limits; security codes have stricter retention rules.
Payment participants: issuers, acquirers and card networks
Cardholders, merchants, issuers, acquirers and networks have different payment roles. Follow authorization, capture and settlement to identify the handling party.
Merchant payment services: PSPs, gateways and MCCs
PSPs, gateways, processors, MIDs, MCCs and MoRs have different merchant-side roles. Compare payment routing, merchant identity, categories and billing descriptions.
Authorization and declines: soft declines, hard declines and codes
Authorization checks whether a payment can proceed. Compare soft and hard declines and authentication requirements with orders and holds before retrying.
From preauthorization to refunds: capture, clearing and settlement
Preauthorization, capture, clearing and settlement are separate stages. Reversals, refunds and chargebacks differ; check transaction status before acting.
Transaction types: card-not-present, ecommerce and recurring payments
Card-not-present, ecommerce, customer-initiated and merchant-initiated transactions differ. Review authentication, funding and recurring-payment records.
Account verification, zero-amount authorizations and billing descriptors
Zero-amount authorizations, small verification holds and purchases differ. Match authorization status, billing descriptors and orders before buying again.
Tokenization and digital wallets: payment tokens and enrollment
Payment and network tokens differ from encrypted card numbers. Review wallet enrollment and card updates; replacement and closure affect recurring billing differently.
PCI DSS and data security: encryption, masking and HSMs
PCI DSS sets card-data protection requirements by role and activity. Citing the standard does not establish platform certification or backend implementation.
Fraud and risk signals: card testing, enumeration and ATO
Card testing, enumeration and account takeover target different data. Preserve records of unknown transactions or logins and report them through official channels.
Disputes and chargebacks: reason codes, appeals and ratios
Merchant refunds, authorization reversals and chargebacks involve different parties. Review evidence and deadlines separately from platform balance refunds.
KYC, KYB, AML and cross-border compliance terms
KYC and KYB verify identity; AML involves ongoing controls. Cross-border fees, currency conversion and DCC affect pricing and need separate checks.