Reference

    Payment & Fintech Glossary

    A comprehensive reference of key terms and concepts in payments, fintech, and payment service provider selection — from acquirers to webhooks.

    #

    3D Secure (3DS)

    An authentication protocol that adds an additional verification step during online card transactions. 3DS2 is the current version, providing a frictionless authentication experience while meeting SCA requirements under PSD2.

    A

    Account Takeover (ATO)

    A type of fraud where a criminal gains unauthorized access to a legitimate user's account, typically through stolen credentials, phishing, or social engineering. ATO is used to make fraudulent purchases, change account details, or extract stored payment methods.

    Account-to-Account Payments (A2A)

    Payments that move funds directly between bank accounts without an intermediary card network. A2A payments leverage Open Banking APIs or bank transfer rails (e.g., SEPA, Faster Payments) and typically offer lower fees than card-based transactions.

    ACH (Automated Clearing House)

    A US-based electronic funds transfer network that processes batch payments between banks. ACH supports both credits (payroll, vendor payments) and debits (bill pay, subscriptions). It is slower but cheaper than wire transfers.

    Bank Transfers Course

    Acquirer (Acquiring Bank)

    A financial institution that processes card payments on behalf of a merchant. The acquirer connects to the card networks, handles authorization requests, and settles funds into the merchant's account. Also known as the merchant's bank.

    Card Payments Course

    Acquirer Markup

    The fee charged by the acquiring bank or PSP on top of interchange and scheme fees. The acquirer markup compensates the acquirer for transaction processing, risk management, customer support, and other services.

    Acquirer Reference Number (ARN)

    A unique 23-digit tracking number assigned by the acquirer to each card transaction. ARNs are used to trace funds through the payment chain — from acquirer to card network to issuer — and are essential for resolving disputes, chargebacks, and refund inquiries.

    Afterpay (Clearpay)

    A BNPL service (owned by Block/Square) that allows consumers to split purchases into four interest-free installments paid every two weeks. Known as Clearpay in the UK and Europe, it is widely integrated in fashion and retail e-commerce.

    Agentic Commerce

    A commerce model where autonomous AI agents act on behalf of consumers or businesses to discover products, negotiate terms, and execute payments with minimal human intervention. Agentic commerce introduces new requirements for identity, authorization, and payment orchestration.

    Agentic Commerce Article

    Alipay

    A digital wallet and payment platform operated by Ant Group (Alibaba affiliate) and the dominant mobile payment method in China. Alipay supports online and in-store payments, cross-border transactions, and a range of financial services for over one billion users.

    Digital Wallets Course

    Anti-Money Laundering (AML)

    A set of laws, regulations, and procedures designed to prevent criminals from disguising illegally obtained funds as legitimate income. AML compliance is mandatory for all payment service providers and financial institutions.

    API (Application Programming Interface)

    A set of protocols and tools that allows different software applications to communicate. In payments, APIs are used to initiate transactions, query balances, manage refunds, and retrieve reporting data from PSPs.

    Apple Pay

    A mobile payment and digital wallet service by Apple that allows users to make contactless payments in stores using NFC and online payments through Safari and apps. Apple Pay tokenizes card credentials and uses biometric authentication (Face ID, Touch ID) for security.

    Digital Wallets Course

    Authentication

    The process of verifying the cardholder's identity during a transaction. Authentication methods include 3D Secure (online), PIN entry (in-store), biometric verification (mobile wallets), and signature. Strong authentication reduces fraud liability for the merchant.

    Authorization

    The process by which a payment transaction is approved or declined by the card issuer. During authorization, the issuer checks whether the cardholder has sufficient funds or credit and whether the transaction passes fraud screening.

    Authorization Code

    A unique alphanumeric code returned by the issuing bank when a card transaction is approved. The authorization code confirms the transaction was validated and serves as a reference for subsequent operations like capture, void, or dispute resolution.

    Authorization Hold

    A temporary hold placed on funds in the cardholder's account after a successful authorization but before capture. The hold reduces the available balance without debiting the account. Authorization holds expire if not captured within the acquirer's time window (typically 7-30 days).

    Authorization Rate

    The percentage of payment transactions that are successfully approved by the issuer. A high authorization rate indicates good payment flow health. Factors affecting auth rates include data quality, tokenization, network tokens, and retry logic.

    AVS (Address Verification Service)

    A fraud prevention tool that compares the billing address provided by the cardholder with the address on file at the issuing bank. AVS returns a match code indicating full, partial, or no match, helping merchants assess transaction risk.

    B

    Bancontact

    The dominant debit card and online payment method in Belgium. Bancontact allows consumers to pay in-store via card or contactless, and online through a redirect to their banking app. It covers the vast majority of Belgian e-commerce payments.

    Bank Transfer

    A payment method where funds are transferred directly between bank accounts through banking infrastructure such as SEPA, ACH, or Faster Payments. Bank transfers are commonly used for high-value payments, B2B transactions, and recurring bills.

    Bank Transfers Course

    Batch Processing

    The practice of grouping multiple payment transactions together for processing at scheduled intervals rather than in real-time. Batch processing is common in ACH, SEPA Direct Debit, and end-of-day settlement with acquirers.

    Batch Settlement

    A settlement model where all transactions processed within a defined period (typically one business day) are grouped together and settled as a single transfer. Most acquirers and PSPs use batch settlement with daily cutoff times.

    Beneficial Owner

    The natural person who ultimately owns or controls a legal entity. AML regulations require financial institutions and PSPs to identify and verify beneficial owners — typically individuals holding 25% or more ownership — during merchant onboarding.

    BIN (Bank Identification Number)

    The first six to eight digits of a payment card number that identify the issuing bank, card brand, card type (credit/debit), and country of issuance. BIN data is used for routing, fraud screening, and interchange optimization.

    Bitcoin (BTC)

    The first and most widely recognized cryptocurrency, created in 2009 by the pseudonymous Satoshi Nakamoto. Bitcoin operates on a proof-of-work blockchain and is used as a store of value, medium of exchange, and the base currency for many crypto payment flows.

    Blockchain Course

    Blended Pricing

    A simplified card pricing model where the PSP charges a single flat rate per transaction regardless of card type or interchange category. Blended pricing is easy to understand but offers less cost transparency than IC++.

    Card Pricing Models

    Block Confirmation

    The number of subsequent blocks added to the blockchain after a transaction's block, indicating the level of finality. More confirmations mean higher security — Bitcoin merchants typically wait for 1-6 confirmations, while stablecoin transactions on Ethereum may require fewer.

    Block Explorer

    A web-based tool that allows users to search and view blockchain data, including transactions, wallet balances, block details, and smart contract interactions. Examples include Etherscan (Ethereum), Blockchain.com (Bitcoin), and Solscan (Solana).

    Blockchain

    A distributed, immutable digital ledger that records transactions across a network of computers. Each block contains a cryptographic hash of the previous block, creating a tamper-resistant chain. Blockchains underpin cryptocurrencies and enable decentralized applications.

    Blockchain Course

    Boleto Bancário

    A popular cash-based payment method in Brazil that generates a voucher (boleto) which customers can pay at banks, post offices, ATMs, or through online banking. Boletos are essential for reaching unbanked and underbanked consumers in Latin America.

    Bridging

    The process of transferring cryptocurrency or tokens from one blockchain network to another using a cross-chain bridge. Bridges enable interoperability but introduce security risks — several major exploits have targeted bridge protocols.

    Buy Now, Pay Later (BNPL)

    A point-of-sale financing option that allows consumers to split a purchase into installments, often interest-free. BNPL providers like Klarna, Afterpay, and Affirm handle credit risk and pay the merchant upfront, minus a fee.

    C

    Capture

    The process of finalizing a previously authorized card transaction to initiate fund transfer. Authorization reserves the funds; capture instructs the acquirer to collect them. Merchants may capture immediately or delay capture until fulfillment.

    Card Brand (Card Scheme)

    The organization that owns and operates the card payment network and sets its rules. Major card brands include Visa, Mastercard, American Express, UnionPay, Discover, JCB, and Diners Club. Each brand defines interchange rates, data standards, and acceptance requirements.

    Card Payments Course

    Card Network (Card Scheme)

    An organization that sets the rules, standards, and infrastructure for card-based payments. The major global card networks are Visa, Mastercard, American Express, and UnionPay. They facilitate communication between issuers and acquirers.

    Card Payments Course

    Card Present (CP)

    A transaction where the physical card is present and used at the point of sale, typically via chip (EMV), contactless (NFC), or magnetic stripe. Card-present transactions have lower fraud rates and interchange fees than card-not-present transactions.

    Card Testing (BIN Attack)

    A fraud technique where criminals use automated scripts to test large batches of stolen card numbers with small transactions. Successful authorizations confirm the card is active, after which larger fraudulent purchases are attempted.

    Card-Not-Present (CNP)

    A transaction where the physical card is not presented to the merchant, such as online, phone, or mail-order purchases. CNP transactions carry higher fraud risk and typically incur higher interchange fees than card-present transactions.

    Card-on-File (CoF)

    A stored payment credential that a merchant keeps with the cardholder's consent for future transactions. Card-on-file enables one-click checkout, subscriptions, and auto-renewals. Card network rules require merchants to identify CoF transactions and obtain proper consent.

    Cardholder

    The individual or entity to whom a payment card is issued. The cardholder is authorized to use the card for purchases and is ultimately responsible for paying the issuer for transactions made on the card.

    Cascade (Payment Routing)

    A payment orchestration strategy where a declined transaction is automatically retried through an alternative PSP or acquirer. Cascading helps recover revenue from soft declines and improves overall authorization rates.

    Cash on Delivery (COD)

    A payment method where the customer pays in cash when the goods are delivered. COD remains significant in markets with lower digital payment penetration, such as parts of the Middle East, Southeast Asia, and Africa.

    CBDC (Central Bank Digital Currency)

    A digital form of a country's fiat currency issued and regulated by its central bank. CBDCs aim to combine the efficiency of digital payments with the stability of government-backed money. The digital euro, digital yuan, and digital dollar are prominent CBDC initiatives.

    CEX (Centralized Exchange)

    A cryptocurrency exchange operated by a central company that acts as an intermediary between buyers and sellers. CEXs (e.g., Coinbase, Binance, Kraken) offer high liquidity, fiat on/off ramps, and custody services but require users to trust the platform with their funds.

    CFT (Counter-Financing of Terrorism)

    Regulatory measures designed to prevent the use of financial systems to fund terrorist activities. CFT obligations are closely linked to AML requirements and apply to all payment service providers and financial institutions.

    Chargeback

    A forced reversal of a card payment initiated by the cardholder's issuing bank. Chargebacks can result from fraud, disputes over goods or services, or processing errors. High chargeback rates can lead to penalties or account termination by the acquirer.

    Chargeback Ratio

    The percentage of total transactions that result in chargebacks over a given period. Card networks monitor chargeback ratios closely — exceeding thresholds (typically 0.9%-1%) can trigger fines, remediation programs, or account termination.

    Checkout Conversion Rate

    The percentage of users who begin the checkout process and successfully complete a payment. Factors affecting checkout conversion include payment method availability, number of steps, page load speed, and trust signals.

    Chip and PIN

    A card-present authentication method where the cardholder inserts their EMV chip card into a terminal and enters a personal identification number (PIN). Chip and PIN is the standard verification method in Europe and provides stronger security than signature-based verification.

    Clearing

    The process of exchanging transaction details between the acquirer and issuer after authorization. During clearing, the final transaction amount is confirmed and prepared for settlement.

    Payments 101 Course

    CNP Fraud

    Fraud committed during card-not-present transactions, typically online. Since the card cannot be physically verified, CNP fraud relies on stolen card details obtained through data breaches, phishing, or social engineering.

    Co-Badged Card

    A payment card that carries two or more card network brands — for example, a Visa and a domestic scheme like Cartes Bancaires (France) or Bancomat (Italy). EU regulations give cardholders and merchants the right to choose which network processes the transaction.

    Cold Wallet (Cold Storage)

    A cryptocurrency storage method where private keys are kept offline on hardware devices or air-gapped computers. Cold wallets provide the highest level of security against hacking and are used for long-term storage of significant crypto holdings.

    Custodial Infrastructure

    Commercial Card

    A payment card issued to businesses rather than individuals, including corporate cards, purchasing cards (P-cards), and fleet cards. Commercial cards typically carry higher interchange fees but provide enhanced data (Level 2/3) for expense management and reconciliation.

    Compliance (Payment Compliance)

    Adherence to the regulatory, legal, and industry standards governing payment processing. This includes PCI DSS for card data security, PSD2 for European payments, AML/KYC requirements, and scheme-specific rules.

    Compliance Officer

    A designated individual within a financial institution or PSP responsible for ensuring adherence to regulatory requirements, including AML, KYC, sanctions screening, and data protection laws.

    Contactless Limit

    The maximum transaction amount allowed for a contactless (tap) payment without requiring PIN entry or additional authentication. Limits vary by country (e.g., £100 in the UK, €50 in most EU countries) and can be higher for mobile wallet transactions authenticated with biometrics.

    Contactless Payment

    A payment method that uses near-field communication (NFC) technology to complete transactions by tapping a card, phone, or wearable device near a payment terminal. Contactless payments are fast, secure, and increasingly preferred for in-store purchases.

    Credit Card

    A payment card issued by a bank that allows the cardholder to borrow funds up to a pre-approved credit limit to pay for goods and services. The cardholder repays the balance monthly, with interest charged on unpaid amounts. Credit cards are the most widely accepted online payment method globally.

    Credit Transfer

    A payment method where the payer instructs their bank to transfer funds directly to the payee's bank account. SEPA Credit Transfers and ACH Credits are common examples used in Europe and the US respectively.

    Bank Transfers Course

    Cross-Border Interchange

    The interchange fee applied when the issuing bank and acquiring bank are in different countries. Cross-border interchange rates are typically higher than domestic rates and may also include additional international assessment fees charged by the card network.

    Cross-Border Payments

    Transactions where the merchant and the customer (or their respective banks) are located in different countries. Cross-border payments involve currency conversion, higher interchange fees, and additional regulatory considerations.

    Crypto PSP

    A payment service provider that enables merchants to accept cryptocurrency and stablecoin payments. Crypto PSPs handle wallet management, transaction processing, and optionally convert digital assets to fiat currency for settlement.

    Crypto PSPs Article

    Crypto-to-Crypto Settlement

    A settlement model where the merchant receives and retains payment in the original cryptocurrency or stablecoin (e.g., USDC, BTC) without converting to fiat. This approach suits businesses that operate natively in the crypto ecosystem or want to hold digital assets.

    Settlement Article

    Crypto-to-Fiat Settlement

    A settlement model where cryptocurrency or stablecoin payments received from customers are automatically converted to fiat currency (e.g., USD, EUR) before being deposited into the merchant's bank account. This eliminates crypto volatility risk for the merchant.

    Settlement Article

    Cryptocurrency Payment

    A payment made using decentralized digital currencies like Bitcoin (BTC), Ethereum (ETH), or stablecoins (USDC, USDT). Crypto payments are processed on blockchain networks and can be facilitated by Crypto PSPs that handle conversion, custody, and settlement.

    Crypto Payments Course

    Custodial Wallet

    A cryptocurrency wallet where a third party (such as a Crypto PSP or exchange) holds and manages the private keys on behalf of the user. This simplifies the user experience but introduces counterparty risk.

    Custodial Infrastructure

    CVV/CVC

    Card Verification Value (Visa) or Card Verification Code (Mastercard) — a three or four-digit security code printed on payment cards. CVV is used in card-not-present transactions to verify that the cardholder has physical possession of the card.

    D

    Data Breach

    An incident where unauthorized parties gain access to sensitive data, including payment card numbers, personal information, or authentication credentials. Data breaches can lead to large-scale fraud and carry significant financial and reputational consequences.

    Debit Card

    A payment card linked directly to the cardholder's bank account. Transactions are funded from available account balances in near real-time. Debit cards typically carry lower interchange fees than credit cards and are commonly used for everyday purchases.

    Decentralized Application (dApp)

    An application that runs on a decentralized blockchain network rather than centralized servers. dApps use smart contracts for their backend logic and are commonly found in DeFi, gaming, NFT marketplaces, and decentralized identity systems.

    Decline Code

    A numeric or alphanumeric code returned by the issuer when a transaction is declined, indicating the reason for the decline. Common decline codes include insufficient funds (51), expired card (54), do not honor (05), and suspected fraud (59). Understanding decline codes helps optimize retry strategies.

    Declined Transaction

    A payment that is rejected by the issuer, card network, or PSP during authorization. Common decline reasons include insufficient funds, suspected fraud, incorrect card details, or expired cards. Soft declines can often be retried.

    Deferred Settlement

    A settlement model where funds are held by the PSP or acquirer for a longer-than-standard period before being released to the merchant. Deferred settlement is used for pre-orders, event tickets, or industries where fulfillment occurs well after payment.

    DeFi (Decentralized Finance)

    A category of financial applications built on blockchain networks that operate without traditional intermediaries like banks. DeFi includes lending, borrowing, trading, insurance, and payment protocols — all governed by smart contracts.

    Device Fingerprinting

    A fraud detection technique that collects attributes of a user's device — such as browser type, operating system, screen resolution, and installed plugins — to create a unique identifier. Device fingerprints help detect suspicious behavior across sessions.

    DEX (Decentralized Exchange)

    A cryptocurrency exchange that operates without a central authority, using smart contracts to facilitate peer-to-peer trading directly from users' wallets. Examples include Uniswap, SushiSwap, and Curve. DEXs provide censorship resistance but may have lower liquidity than centralized exchanges.

    Digital Wallet

    A software application or service that stores payment credentials and allows users to make electronic payments. Examples include Apple Pay, Google Pay, and PayPal. Digital wallets can store cards, bank accounts, or cryptocurrency.

    Digital Wallets Course

    Direct Debit

    A payment method where the payee (merchant) pulls funds directly from the payer's bank account, based on a pre-authorized mandate. SEPA Direct Debit and ACH Debit are widely used for recurring payments like subscriptions and utility bills.

    Bank Transfers Course

    Disbursement

    The distribution of funds from a central account to multiple recipients, such as sellers on a marketplace, employees, or affiliate partners. Disbursements can be made via bank transfer, card push payments, or digital wallets.

    Dual Message

    A card processing model where authorization and clearing/settlement are handled as two separate messages. The first message authorizes the transaction; the second (sent later) initiates clearing and settlement. Dual message is the standard model for credit card transactions.

    Dunning

    The process of communicating with customers to collect failed or overdue subscription payments. Dunning strategies include automated retry schedules, email reminders, and in-app notifications to reduce involuntary churn.

    Dynamic Currency Conversion (DCC)

    A service that allows international cardholders to pay in their home currency rather than the merchant's local currency at the point of sale. DCC typically includes a markup on the exchange rate and is offered by the acquirer or payment terminal provider.

    E

    E-Invoice Payment

    A B2B payment method where a structured electronic invoice is sent to the buyer's accounting or ERP system, enabling automated matching, approval, and payment. E-invoicing is mandatory in many European countries and streamlines the procure-to-pay cycle.

    E-Money License (EMI)

    A regulatory authorization that permits a company to issue electronic money (e-money) and provide payment services. In the EU, an EMI license is required for companies that hold customer funds and facilitate electronic payments outside of traditional banking.

    ECI (Electronic Commerce Indicator)

    A value returned during 3D Secure authentication that indicates the level of authentication achieved. ECI values determine the liability shift status — fully authenticated (ECI 05/02), attempted (ECI 06/01), or non-authenticated (ECI 07/00).

    EDD (Enhanced Due Diligence)

    A deeper level of KYC investigation applied to higher-risk customers, politically exposed persons (PEPs), or complex corporate structures. EDD involves gathering additional documentation, understanding source of funds, and ongoing monitoring.

    Embedded Payments

    The integration of payment processing directly into non-financial software platforms (e.g., SaaS tools, marketplaces, ERP systems) so that users can pay without leaving the application. Embedded payments are a key revenue stream for platform businesses.

    EMV

    A global standard for chip-based payment cards, named after its original developers (Europay, Mastercard, Visa). EMV chips generate unique transaction codes that are more secure than magnetic stripe data, reducing counterfeit fraud.

    Escrow

    A financial arrangement where a trusted third party holds funds until specific conditions are met. In payments, escrow is used in marketplaces and high-value transactions to protect both buyers and sellers until delivery is confirmed.

    Ethereum (ETH)

    A decentralized blockchain platform that supports smart contracts and decentralized applications (dApps). Ethereum's native cryptocurrency, Ether, is used to pay transaction fees (gas). Ethereum hosts the majority of stablecoins, DeFi protocols, and NFT marketplaces.

    F

    Fallback Transaction

    A card transaction processed using a less secure method (e.g., magnetic stripe) when the primary method (e.g., EMV chip) fails. Fallback transactions carry higher fraud risk and may not qualify for liability shift, resulting in higher costs or increased merchant liability.

    Faster Payments

    The UK's real-time bank transfer system that enables near-instant fund transfers between participating banks, 24/7. Faster Payments supports both push payments and Direct Debits with typical settlement in seconds.

    FATF (Financial Action Task Force)

    An intergovernmental body that sets international standards for combating money laundering, terrorist financing, and other financial crimes. FATF recommendations form the basis of AML/CFT regulations worldwide.

    Flexible Settlement

    A settlement model offered by some Crypto PSPs that allows merchants to choose a custom split between fiat and cryptocurrency settlement on a per-transaction or portfolio basis. For example, settling 70% in EUR and 30% in USDC.

    Settlement Article

    Four-Party Model

    The dominant card payment model involving four key participants: the cardholder, the merchant, the issuing bank, and the acquiring bank. Visa and Mastercard operate under this model, with the card network acting as an intermediary between issuers and acquirers.

    Card Payments Course

    Fraud Screening

    The automated process of evaluating payment transactions for potential fraud before they are authorized. Fraud screening tools use rules, machine learning, device fingerprinting, and behavioral analytics to assign risk scores and flag suspicious activity.

    Fraud-as-a-Service (FaaS)

    An underground economy where criminal networks sell fraud tools, stolen credentials, and attack services to other fraudsters. FaaS has lowered the barrier to committing payment fraud and increased the sophistication of attacks.

    Frictionless Authentication

    A 3D Secure 2 flow where the issuer approves the transaction based on risk assessment data without requiring the cardholder to perform any additional action. Frictionless authentication improves checkout conversion while maintaining SCA compliance through risk-based exemptions.

    Friendly Fraud

    A type of chargeback fraud where a legitimate cardholder makes a purchase and then disputes the charge with their issuer, claiming it was unauthorized or that goods were not received. Also known as first-party fraud or chargeback abuse.

    FX (Foreign Exchange)

    The conversion of one currency to another during cross-border payments. FX rates and markups are applied by banks, card networks, or PSPs and can significantly impact the total cost of international transactions.

    G

    Gas Fee

    The transaction fee paid to blockchain validators for processing and confirming transactions on networks like Ethereum. Gas fees fluctuate based on network congestion and transaction complexity. High gas fees have driven the adoption of Layer 2 solutions.

    GDPR (General Data Protection Regulation)

    The European Union's comprehensive data privacy regulation that governs how organizations collect, process, store, and share personal data. GDPR applies to any company processing data of EU residents, including PSPs and merchants.

    Giropay

    A German online bank transfer payment method that allows consumers to pay directly from their bank account. Giropay provides immediate payment confirmation and is integrated into many German banks' online banking platforms.

    Google Pay

    A digital wallet and payment platform by Google that supports contactless in-store payments via NFC, online checkout, and peer-to-peer transfers. Google Pay stores tokenized card credentials and is available on Android devices and web browsers.

    Gross Settlement

    A settlement model where each transaction is settled individually and in full, without netting against other transactions. Gross settlement provides maximum transparency but results in higher transaction volumes between parties. Real-time gross settlement (RTGS) systems like TARGET2 and Fedwire use this approach.

    H

    Hard Decline

    A permanent transaction decline that should not be retried, typically caused by invalid card number, closed account, stolen card, or explicit issuer block. Retrying hard declines wastes resources and may violate card network rules.

    Hash

    A fixed-length alphanumeric string produced by a cryptographic hash function from input data of any size. In blockchain, hashes uniquely identify blocks and transactions, ensure data integrity, and link blocks together in the chain.

    High-Risk Merchant

    A business operating in an industry with elevated chargeback rates, regulatory scrutiny, or reputational risk. Examples include gambling, adult content, nutraceuticals, and cryptocurrency. High-risk merchants face stricter underwriting and higher processing fees.

    Merchant Risk Profile

    Holdback (Settlement Holdback)

    A percentage of settlement funds that the acquirer or PSP temporarily withholds as a risk reserve. Holdbacks protect against potential chargebacks and refunds, and are common for new merchants, high-risk industries, or businesses with limited processing history.

    Hosted Payment Page

    A checkout page hosted and managed by the PSP rather than the merchant. Hosted payment pages reduce PCI scope for the merchant because sensitive card data never touches the merchant's servers. Examples include Stripe Checkout and Adyen's Drop-in.

    Hot Wallet

    A cryptocurrency wallet that is connected to the internet, enabling quick and convenient transactions. Hot wallets are used for day-to-day operations and active trading but are more vulnerable to hacking than cold storage solutions.

    Custodial Infrastructure

    I

    iDEAL

    The most popular online payment method in the Netherlands, enabling consumers to pay directly from their bank account through their own banking app. iDEAL processes over 70% of Dutch e-commerce transactions and provides real-time payment confirmation.

    Digital Wallets Course

    Idempotency

    A property of an API operation that ensures the same request can be made multiple times without producing different results. In payments, idempotency keys prevent duplicate charges when network errors cause retries of payment requests.

    Identity Verification (IDV)

    The process of confirming that a person is who they claim to be, typically using government-issued documents, biometric checks, or database lookups. IDV is a core component of KYC during merchant and customer onboarding.

    Instant Payments

    Payment systems that clear and settle funds in real-time or near-real-time, 24/7/365. Examples include SEPA Instant (Europe), Faster Payments (UK), and FedNow (US). Instant payments are irrevocable once settled.

    Instant Settlement

    A settlement model where funds are transferred to the merchant within minutes of a successful transaction, rather than waiting for batch processing cycles. Instant settlement is offered by some PSPs as a premium feature and relies on real-time payment rails.

    Interchange Category

    A classification that determines the specific interchange rate applied to a transaction. Interchange categories depend on factors including card type (credit/debit), card product (consumer/commercial/premium), merchant category code (MCC), and transaction method (card-present vs. card-not-present).

    Card Pricing Models

    Interchange Fee

    A fee paid by the acquiring bank to the issuing bank for each card transaction. Interchange fees are set by the card networks (Visa, Mastercard) and vary based on card type, merchant category, and region. They represent the largest component of card processing costs.

    Interchange Optimization

    Strategies and practices used by merchants to qualify transactions for the lowest possible interchange rates. Optimization techniques include submitting enhanced data (Level 2/3), settling promptly, using address verification, and ensuring correct MCC classification.

    Interchange Plus Plus (IC++)

    A transparent card pricing model where the merchant pays the actual interchange fee, the card scheme fee, and the acquirer's markup separately. IC++ gives merchants full visibility into cost components and is preferred for high-volume businesses.

    Card Pricing Models

    ISO 20022

    An international standard for financial messaging that provides a common language and model for payments data across the globe. It enables richer, more structured data in payment messages compared to legacy formats like SWIFT MT.

    ISO 20022 Course

    Issuer (Issuing Bank)

    The financial institution that issues payment cards to consumers. The issuer is responsible for authorizing transactions, extending credit or managing debit balances, and handling cardholder disputes.

    K

    Klarna

    A Swedish fintech company and leading Buy Now, Pay Later (BNPL) provider. Klarna offers consumers flexible payment options including pay-in-4 installments, pay-in-30-days, and longer-term financing at checkout. Merchants receive full payment upfront while Klarna assumes credit risk.

    KYC (Know Your Customer)

    The regulatory process of verifying the identity of customers before or during the onboarding process. KYC is a critical component of AML compliance and is required for all financial service providers, including PSPs.

    L

    Layer 1 (L1)

    The base blockchain network that processes and finalizes transactions on its own consensus mechanism. Examples include Bitcoin, Ethereum, Solana, and Avalanche. Layer 1 blockchains provide security and decentralization but may face scalability limitations.

    Layer 2 (L2)

    A secondary protocol built on top of a Layer 1 blockchain to improve scalability and reduce transaction costs. Layer 2 solutions (e.g., Lightning Network for Bitcoin, Arbitrum and Optimism for Ethereum) process transactions off-chain and periodically settle on the main chain.

    Ledger

    A financial record-keeping system that tracks all debits, credits, and balances for accounts. In payments, internal ledgers are used by platforms and marketplaces to track fund flows, commissions, and payouts before reconciling with bank statements.

    Level 2 / Level 3 Data

    Enhanced transaction data submitted with B2B and government card payments to qualify for lower interchange rates. Level 2 includes tax amount and customer reference; Level 3 adds line-item detail (product codes, quantities, unit prices). Primarily relevant for commercial and purchasing cards.

    Liability Shift

    A change in responsibility for fraud losses from the merchant to the issuer (or vice versa) based on authentication and security protocols used. For example, successful 3D Secure authentication typically shifts fraud liability from merchant to issuer.

    Lightning Network

    A Layer 2 payment protocol built on top of the Bitcoin blockchain that enables instant, low-cost micropayments through off-chain payment channels. The Lightning Network is designed to make Bitcoin viable for everyday retail transactions.

    Blockchain Course

    Local Payment Methods (LPMs)

    Payment methods that are popular in specific countries or regions but not widely used globally. Examples include iDEAL (Netherlands), Bancontact (Belgium), Boleto (Brazil), and Alipay (China). Supporting LPMs improves conversion in local markets.

    Digital Wallets Course

    M

    Machine Learning (in Fraud Detection)

    The application of AI algorithms that learn from historical transaction data to identify patterns associated with fraud. ML models continuously adapt to new fraud tactics, improving detection accuracy while reducing false positives over time.

    Magnetic Stripe

    A strip of magnetic material on the back of a payment card that stores cardholder data. Magnetic stripes are considered less secure than EMV chips because the static data can be copied (skimmed). Many regions are phasing out magnetic stripe support.

    Mandate

    A written or electronic authorization from a payer that allows a merchant to initiate Direct Debit transactions from their bank account. Mandates specify the terms and must be obtained before the first collection.

    Marketplace Payments

    Payment flows designed for multi-sided platforms where transactions involve a buyer, a seller, and the platform operator. Marketplace payments require split settlement, seller onboarding, and often involve regulatory considerations around fund holding.

    Merchant Models

    Mastercard SecureCode

    Mastercard's implementation of the 3D Secure authentication protocol, now operating under the Mastercard Identity Check brand for 3DS2. It adds an authentication layer during online card transactions to verify the cardholder's identity and enable liability shift.

    Mempool

    The queue of unconfirmed transactions waiting to be included in the next block by miners or validators. Transactions with higher fees are typically prioritized. Monitoring the mempool helps estimate confirmation times and optimal fee levels.

    Merchant Account

    A specialized bank account that enables a business to accept card payments. Funds from card transactions are deposited into the merchant account before being transferred to the business's regular bank account.

    Merchant Category Code (MCC)

    A four-digit code assigned by card networks to classify a merchant's primary business activity. MCCs influence interchange rates, determine eligibility for certain card programs, and are used in expense management and regulatory reporting.

    Merchant Discount Rate (MDR)

    The total percentage fee a merchant pays to accept a card payment. MDR typically includes interchange, scheme fees, and acquirer markup combined into a single rate, especially under blended pricing models.

    Merchant of Record (MoR)

    The legal entity that is recognized by the card networks and payment providers as the seller in a transaction. The MoR bears liability for chargebacks, refunds, and regulatory compliance. Platforms sometimes use a third-party MoR to simplify international expansion.

    MoR Article

    MiCA (Markets in Crypto-Assets Regulation)

    A comprehensive EU regulation establishing a harmonized framework for crypto-asset issuers and service providers. MiCA covers licensing, consumer protection, stablecoin reserves, and operational requirements for crypto businesses operating in Europe.

    Crypto Payments Course

    Mining

    The process of using computational power to validate transactions and add new blocks to a proof-of-work blockchain. Miners are rewarded with newly created cryptocurrency and transaction fees. Bitcoin mining secures the network through energy-intensive computation.

    Mobile Money

    A financial service that allows users to store, send, and receive money using a mobile phone, without needing a traditional bank account. Mobile money (e.g., M-Pesa, MTN Mobile Money) is widely used in Sub-Saharan Africa and parts of Asia for payments, remittances, and savings.

    MPC (Multi-Party Computation)

    A cryptographic technique used in wallet security where the private key is split into multiple shares held by different parties. No single party ever holds the complete key. MPC enables institutional-grade custody without the UX friction of traditional multisig.

    Custodial Infrastructure

    Multi-Currency Pricing (MCP)

    A pricing strategy where merchants display prices in the customer's local currency while settling in their own preferred currency. MCP improves customer experience and conversion rates for international buyers.

    Multi-Currency Settlement

    A settlement arrangement where the PSP or acquirer deposits funds in the original transaction currency rather than converting to a single base currency. Multi-currency settlement helps international merchants avoid unnecessary FX conversions and associated costs.

    Multi-Signature (Multisig)

    A wallet security mechanism that requires multiple private key signatures to authorize a transaction. For example, a 2-of-3 multisig wallet requires any two of three designated key holders to approve a transfer. Multisig is widely used for institutional custody and treasury management.

    N

    Net Settlement

    A settlement model where multiple transactions between parties are aggregated and only the net difference is transferred. Net settlement reduces the number and volume of fund movements, lowering costs and liquidity requirements. Most card networks and ACH systems use net settlement.

    Network Token

    A token issued by a card network (Visa, Mastercard) that replaces the primary account number (PAN) for secure digital transactions. Network tokens improve authorization rates, reduce fraud, and automatically update when a card is reissued.

    NFC (Near Field Communication)

    A short-range wireless technology that enables contactless payments by allowing two devices to exchange data when placed within a few centimeters of each other. NFC powers tap-to-pay for cards, phones, and wearables.

    NFT (Non-Fungible Token)

    A unique digital asset recorded on a blockchain that represents ownership of a specific item — such as digital art, collectibles, music, or in-game assets. Unlike fungible tokens (e.g., USDC), each NFT is one-of-a-kind and cannot be exchanged interchangeably.

    O

    Off-Ramp

    A service that allows users to convert cryptocurrency back into fiat currency and withdraw to a bank account. Off-ramps are essential for merchants who accept crypto payments but want to settle in fiat, and for individuals cashing out holdings.

    Omnichannel Payments

    A unified payment strategy that provides a consistent customer experience across all channels — online, in-store, mobile, and call center. Omnichannel payments require integrated systems that share customer, order, and payment data.

    Payment Channels

    On-Ramp

    A service that allows users to convert fiat currency (e.g., USD, EUR) into cryptocurrency. On-ramps include exchanges, payment providers, and embedded widgets that accept bank transfers or card payments in exchange for crypto. Also known as fiat-to-crypto gateway.

    Open Banking

    A regulatory and technology framework that allows third-party providers to access bank account data and initiate payments through secure APIs, with the account holder's consent. Open Banking was introduced in Europe under PSD2 and is expanding globally.

    Open Banking Payment

    A bank transfer initiated through a third-party provider using Open Banking APIs (under PSD2). Open Banking payments offer real-time confirmation, lower fees than card payments, and strong authentication — making them increasingly popular for e-commerce and bill payments.

    Oracle

    A service that provides external real-world data (e.g., asset prices, weather, sports results) to smart contracts on the blockchain. Oracles like Chainlink bridge the gap between on-chain logic and off-chain information, enabling more complex decentralized applications.

    P

    PAN (Primary Account Number)

    The 14-19 digit number embossed or printed on a payment card that uniquely identifies the cardholder's account. The PAN is sensitive data and should be tokenized or encrypted to meet PCI DSS requirements.

    Partial Authorization

    An authorization where the issuer approves only a portion of the requested amount due to insufficient funds or credit limit. The merchant can either accept the partial amount and request the remainder through another payment method, or void the transaction.

    Payment Credential

    The data required to identify and authorize a payment — for cards this includes the PAN, expiry date, and CVV. Modern payment systems increasingly replace raw credentials with tokens to reduce fraud risk and PCI scope.

    Payment Facilitator (PayFac)

    A type of merchant acquirer that onboards sub-merchants under its own master merchant account. PayFacs simplify onboarding for platforms and marketplaces by handling underwriting, compliance, and settlement on behalf of their sub-merchants. Examples include Stripe and Square.

    Payment Gateway

    A technology service that captures and transmits payment data from the merchant's checkout to the acquirer or payment processor. The gateway encrypts sensitive information and routes authorization requests to the appropriate networks.

    Payment Intent

    An API object (used by PSPs like Stripe) that represents a customer's intention to make a payment. The payment intent tracks the lifecycle of a transaction from creation through authentication, authorization, and capture.

    Payment Method

    The specific instrument or mechanism a consumer uses to pay for goods or services. Common payment methods include credit cards, debit cards, bank transfers, digital wallets, BNPL, and cryptocurrency.

    Payment Orchestration

    A layer of software that sits between a merchant and multiple PSPs or acquirers, enabling intelligent routing, failover, and optimization of payment transactions across providers. Payment orchestration platforms help improve authorization rates and reduce costs.

    Payment Processor

    A company that handles the technical processing of payment transactions between the merchant, acquirer, card network, and issuer. Payment processors manage authorization, clearing, and settlement messaging on behalf of acquirers.

    Payment Rails

    The underlying infrastructure and networks through which payments are routed and processed. Different payment rails include card networks (Visa, Mastercard), bank transfer systems (SEPA, ACH), and real-time payment systems (Faster Payments, FedNow).

    Payment Service Provider (PSP)

    A company that provides merchants with the technology and services needed to accept electronic payments. PSPs typically offer payment gateway services, acquiring, fraud prevention, and reporting. Examples include Stripe, Adyen, Checkout.com, and Mollie.

    Provider Selection

    Payout

    The transfer of funds from a platform, marketplace, or PSP to a seller, service provider, or merchant. Payouts can be scheduled (daily, weekly) or triggered on demand, and may involve currency conversion for cross-border recipients.

    PayPal

    A global digital payment platform that enables online payments, money transfers, and merchant services. PayPal acts as an intermediary between consumers and merchants, allowing users to pay with stored cards, bank accounts, or PayPal balance without sharing financial details with the merchant.

    PCI DSS

    Payment Card Industry Data Security Standard — a set of security requirements designed to ensure that all companies that process, store, or transmit credit card information maintain a secure environment. Compliance levels range from SAQ-A (lowest) to Level 1 (highest).

    PEP (Politically Exposed Person)

    An individual who holds or has held a prominent public function, such as a head of state, senior politician, or military leader. PEPs and their close associates are subject to enhanced due diligence under AML regulations due to higher corruption risk.

    Phishing

    A social engineering attack where fraudsters impersonate legitimate organizations via email, SMS, or fake websites to trick individuals into revealing sensitive information such as login credentials, card numbers, or personal data.

    PIN Bypass

    A feature that allows a card-present transaction to proceed without PIN entry, typically for low-value transactions or when the terminal cannot process PIN verification. PIN bypass rules vary by card network and region.

    PIX

    Brazil's instant payment system launched by the Central Bank, enabling real-time 24/7 fund transfers between individuals, businesses, and government entities using QR codes, phone numbers, or email as payment keys. PIX has rapidly become the most used payment method in Brazil.

    POS (Point of Sale)

    The physical or digital location where a retail transaction is completed. A POS system includes hardware (terminal, card reader) and software for processing payments, managing inventory, and generating receipts.

    Pre-Authorization

    A hold placed on funds in a cardholder's account to verify available credit or balance without completing the transaction. Pre-authorizations are common in hotels, car rentals, and gas stations where the final amount is unknown at checkout.

    Prepaid Card

    A payment card loaded with a fixed amount of funds in advance, not linked to a bank account or credit line. Prepaid cards are used for gifting, corporate expenses, payroll disbursements, and by consumers without traditional bank accounts.

    Private Key

    A cryptographic key that provides ownership and control over a blockchain wallet and its funds. The private key is used to sign transactions and must be kept secret — anyone with access to the private key can spend the associated cryptocurrency.

    Blockchain Course

    Processing Fee

    The fee charged by the payment processor or PSP for handling each transaction, separate from interchange and scheme fees. Processing fees may be a flat rate, a percentage, or a combination, and cover the cost of authorization routing, fraud screening, and settlement.

    Proof of Stake (PoS)

    A blockchain consensus mechanism where validators are selected to create new blocks based on the amount of cryptocurrency they have staked as collateral. PoS is more energy-efficient than Proof of Work and is used by Ethereum (post-Merge), Solana, and Cardano.

    Proof of Work (PoW)

    A blockchain consensus mechanism where miners compete to solve complex mathematical puzzles to validate transactions and create new blocks. PoW is used by Bitcoin and provides strong security but requires significant energy consumption.

    PSD2 (Payment Services Directive 2)

    A European regulation governing electronic payments. PSD2 introduced Strong Customer Authentication (SCA), opened banking APIs to third-party providers (Open Banking), and strengthened consumer protection for digital payments.

    PSD3 (Payment Services Directive 3)

    The proposed update to PSD2 that aims to strengthen consumer protection, improve Open Banking, address fraud, and update the regulatory framework for payment services in the European Union. PSD3 is expected to introduce stricter liability rules and enhanced SCA requirements.

    Public Key

    A cryptographic key derived from the private key that serves as an address for receiving cryptocurrency. Public keys can be shared openly and are used by others to send funds to the wallet. They cannot be used to reverse-engineer the private key.

    Q

    QR Code Payment

    A payment method where the customer scans a QR code displayed by the merchant (or vice versa) to initiate a transaction through a mobile app or digital wallet. QR payments are dominant in Asia (Alipay, WeChat Pay) and growing in Europe and Latin America (PIX).

    R

    Reconciliation

    The process of matching payment transaction records from the PSP with internal business records (ERP, accounting, order management). Automated reconciliation ensures accuracy, speeds up financial close, and reduces manual effort.

    Reconciliation Article

    Recurring Payments

    Automatic, scheduled payments for subscriptions, memberships, or installment plans. Recurring payments can be card-based (using tokens) or bank-based (using Direct Debit mandates) and require special handling for card updates and retries.

    Recurring Transaction Indicator

    A flag in the transaction data that identifies the payment as part of a recurring series (subscription, installment). Card networks require merchants to properly mark recurring transactions to ensure correct authentication, interchange classification, and consumer protections.

    Refund

    A reversal of a completed payment where funds are returned to the customer's original payment method. Refunds can be full or partial and are typically initiated by the merchant through the PSP. Processing times vary by payment method.

    Representment

    The process by which a merchant disputes a chargeback by submitting compelling evidence to the acquirer, who presents it to the issuer on the merchant's behalf. Successful representment reverses the chargeback and returns the funds to the merchant.

    Request to Pay (RtP)

    A messaging framework that allows a payee to send a digital payment request to a payer, who can then approve, decline, or negotiate the payment. RtP works alongside real-time payment rails and is positioned as a modern alternative to Direct Debit for bill payments.

    Reserve (Rolling Reserve)

    A percentage of transaction volume that an acquirer or PayFac withholds as a risk buffer against potential chargebacks, refunds, or fraud losses. Reserves are common for new merchants or those in high-risk categories.

    Retrieval Request

    A request from the issuing bank asking the merchant to provide documentation about a specific transaction, often as a precursor to a chargeback. Responding promptly with transaction evidence can help prevent the retrieval from escalating to a formal dispute.

    Return

    In Direct Debit, a return occurs when the payer's bank rejects the transaction — either before settlement (e.g., insufficient funds) or after (e.g., unauthorized mandate). Returns are similar to chargebacks in the card world.

    Reversal

    A message sent to cancel a previously authorized transaction before settlement occurs. Reversals release the authorization hold on the cardholder's account and are distinct from refunds, which occur after settlement. Timely reversals improve the cardholder experience.

    Risk Scoring

    The process of assigning a numerical risk score to a payment transaction based on fraud indicators, customer behavior, device fingerprinting, and historical patterns. Risk scores help merchants decide whether to accept, review, or decline a transaction.

    Risk-Based Authentication (RBA)

    An authentication approach that adjusts the level of verification required based on the assessed risk of a transaction. Low-risk transactions may pass without friction, while high-risk ones trigger additional steps like 3D Secure or biometric checks.

    Rolling Settlement

    A continuous settlement process where transactions are settled on a fixed schedule relative to their processing date (e.g., every transaction settles T+2 from when it was captured), rather than being batched into a single daily or weekly cycle.

    Rug Pull

    A type of crypto fraud where project developers abandon a project and abscond with investor funds after raising capital through token sales or liquidity pools. Rug pulls are most common in DeFi and meme token projects with anonymous teams.

    S

    Same-Day Settlement

    A settlement option where funds from processed transactions are deposited into the merchant's bank account on the same business day. Same-day settlement improves cash flow but may carry additional fees from the PSP or acquirer.

    Sanctions Screening

    The process of checking individuals, entities, and transactions against government and international sanctions lists (e.g., OFAC, EU Consolidated List, UN). Sanctions screening is mandatory for all financial institutions and PSPs to prevent prohibited transactions.

    Sandbox

    A testing environment provided by a PSP that simulates live payment processing without moving real funds. Sandboxes allow developers to test payment integrations, error handling, and edge cases before going live.

    SAQ (Self-Assessment Questionnaire)

    A PCI DSS compliance validation tool that merchants complete to assess their card data security practices. Different SAQ types (A, A-EP, B, C, D) apply based on how the merchant handles cardholder data.

    SAR (Suspicious Activity Report)

    A regulatory filing submitted by financial institutions or PSPs to national authorities when a transaction or pattern of behavior raises suspicion of money laundering, fraud, or other financial crimes.

    SCA Exemptions

    Specific transaction categories under PSD2 that do not require Strong Customer Authentication. Exemptions include low-value transactions (under €30), trusted beneficiaries, recurring payments, and transactions assessed as low-risk through Transaction Risk Analysis (TRA).

    Scheme Fee

    A fee charged by the card network (Visa, Mastercard) for each transaction processed through its network. Scheme fees are separate from interchange fees and cover the cost of network infrastructure, brand licensing, and innovation programs.

    Scheme Token

    A token issued directly by a card scheme (Visa or Mastercard) that maps to the underlying card number. Scheme tokens provide better authorization rates than PSP-level tokens because they are recognized by issuers as first-party credentials.

    Scheme Token vs. PSP Token

    Scheme tokens are issued by card networks (Visa, Mastercard) and recognized by issuers globally, offering higher auth rates and lifecycle management. PSP tokens are generated by the payment provider and only valid within that PSP's ecosystem. Scheme tokens are generally preferred for recurring and card-on-file transactions.

    Scope Blueprint

    A structured document that defines all payment integration requirements before development begins. A Scope Blueprint typically covers business model, payment methods, regions, compliance needs, settlement preferences, and technical integration requirements.

    Create a Scope Blueprint

    Secure Element

    A tamper-resistant hardware component in a device (phone, card, or terminal) that securely stores sensitive data such as cryptographic keys and payment credentials. Secure elements are used in EMV cards and NFC-enabled mobile wallets.

    Seed Phrase (Recovery Phrase)

    A series of 12 or 24 words generated when creating a cryptocurrency wallet that can be used to recover the wallet and its funds if the device is lost. The seed phrase is the master backup for all private keys in the wallet and must be stored securely offline.

    Self-Custody

    A model where the user retains full control over their cryptocurrency private keys and funds without relying on a third party. Self-custody provides maximum sovereignty but places the burden of security, backup, and key management entirely on the user.

    Custodial Infrastructure

    SEPA (Single Euro Payments Area)

    A payment integration initiative of the European Union that standardizes euro-denominated bank transfers across 36 European countries. SEPA includes Credit Transfers (SCT), Direct Debits (SDD), and Instant Credit Transfers (SCT Inst).

    Bank Transfers Course

    SEPA Credit Transfer (SCT)

    A euro-denominated bank transfer scheme that enables individuals and businesses to send payments across 36 European countries using a standardized format. SCT transactions typically settle within one business day.

    Bank Transfers Course

    SEPA Direct Debit (SDD)

    A pull-based payment scheme that allows creditors to collect euro payments from a debtor's bank account across SEPA countries, based on a signed mandate. SDD comes in two variants: Core (for consumers) and B2B (for businesses).

    Bank Transfers Course

    SEPA Instant Credit Transfer (SCT Inst)

    An extension of SEPA Credit Transfer that settles payments in less than 10 seconds, 24/7/365. SCT Inst supports transfers up to €100,000 and is becoming the standard for real-time euro payments across Europe.

    Settlement

    The final step in the payment process where funds are transferred from the acquiring bank to the merchant's bank account. Settlement can occur in real-time, same-day, or on a T+1/T+2 basis depending on the payment method and provider.

    Settlement Article

    Settlement Account

    The designated bank account where a PSP or acquirer deposits the merchant's processed funds after settlement. Merchants may maintain multiple settlement accounts in different currencies or jurisdictions to optimize treasury operations.

    Settlement Cycle

    The end-to-end timeframe from transaction capture to fund deposit in the merchant's account. Settlement cycles vary by payment method — card payments typically settle in 1-2 business days, bank transfers in 1-3 days, and instant payments in seconds.

    Settlement Report

    A detailed report provided by the PSP or acquirer that lists all transactions included in a settlement batch, along with fees, chargebacks, refunds, and the net amount deposited. Settlement reports are essential for reconciliation.

    Reconciliation Article

    Single Message

    A card processing model where authorization and financial clearing occur in a single message exchange. Common for debit card transactions at POS terminals, where the amount is immediately debited from the cardholder's account upon authorization.

    Skimming

    A type of card fraud where a device is secretly installed on an ATM or POS terminal to capture card data from the magnetic stripe. EMV chip technology has significantly reduced skimming fraud at card-present terminals.

    Slippage

    The difference between the expected price of a crypto trade and the actual execution price, caused by market volatility or low liquidity. In payment processing, slippage affects the final fiat value when converting crypto payments in real-time.

    Smart Contract

    A self-executing program stored on a blockchain that automatically enforces the terms of an agreement when predefined conditions are met. Smart contracts eliminate the need for intermediaries and are used in DeFi, token issuance, escrow, and automated payment flows.

    Soft Decline

    A temporary transaction decline that may succeed if retried. Soft declines are often caused by issuer timeouts, network issues, or temporary holds. Smart retry logic can recover a significant percentage of soft-declined transactions.

    Source of Funds (SOF)

    Documentation or evidence that demonstrates the origin of a customer's money. Source of funds verification is part of enhanced due diligence and is required for high-value transactions or high-risk customer relationships.

    Split Payments

    A payment model where a single transaction is divided and distributed to multiple recipients. Common in marketplaces and platforms where the payment amount is split between the seller, the platform (commission), and potentially other parties like service providers.

    Merchant Models

    Split Settlement

    A settlement arrangement where a single payment is automatically divided and deposited into multiple accounts. Common in marketplace models where the platform, seller, and potentially other parties (tax authorities, service providers) each receive their share directly from the PSP.

    Merchant Models

    Stablecoin

    A type of cryptocurrency designed to maintain a stable value by being pegged to a reserve asset, typically a fiat currency like the US Dollar. USDC and USDT are popular stablecoins used in payment processing due to their price stability.

    Crypto Payments Course

    Staking

    The process of locking up cryptocurrency as collateral to participate in a proof-of-stake blockchain's consensus mechanism. Stakers earn rewards for validating transactions. Staking also refers to depositing tokens in DeFi protocols to earn yield.

    Stored Credential

    A payment credential (card number or token) that a cardholder has authorized a merchant to store for future use. Stored credentials power one-click payments, subscriptions, and auto-top-ups. Card network rules require merchants to flag stored credential transactions appropriately.

    Strong Customer Authentication (SCA)

    A requirement under PSD2 that mandates two-factor authentication for most electronic payments in the European Economic Area. SCA requires at least two of three elements: something the customer knows, has, or is.

    Surcharge Fee

    An additional fee added by the merchant to a transaction when the customer pays by card. Surcharging is permitted in some jurisdictions (e.g., Australia, parts of the US) but prohibited in others (e.g., EU under PSD2 for consumer cards). Rules vary by card network and region.

    Surcharging

    The practice of adding a fee to a transaction when a customer pays with a specific payment method, typically a credit card. Surcharging regulations vary by country and card network — it is banned in some jurisdictions.

    SWIFT

    The Society for Worldwide Interbank Financial Telecommunication — a global messaging network used by banks and financial institutions to securely exchange payment instructions. SWIFT codes (BIC) identify specific banks in international wire transfers.

    ISO 20022 Course

    T

    T+1 / T+2 Settlement

    Settlement timing conventions indicating that funds are transferred one (T+1) or two (T+2) business days after the transaction date. Card payments typically settle on T+1 or T+2 depending on the acquirer, while some PSPs offer faster or same-day options.

    Terminal

    A physical device that accepts payment cards at the point of sale. Modern terminals support chip (EMV), contactless (NFC), and mobile wallet payments. They connect to the acquirer to authorize and process transactions.

    Three-Party Model

    A card payment model where the card network also acts as both the issuer and acquirer. American Express and Discover operate under this model, giving them direct relationships with both cardholders and merchants.

    Card Payments Course

    Token

    A digital asset created on an existing blockchain (as opposed to a native cryptocurrency like ETH or BTC). Tokens can represent currencies (stablecoins), utility access, governance rights, or real-world assets. ERC-20 is the most common token standard on Ethereum.

    Tokenization

    The process of replacing sensitive payment data (such as a card number) with a non-sensitive equivalent called a token. Tokens can be used for recurring payments and stored safely without increasing PCI scope.

    Transaction Fee

    A fee charged per payment transaction, typically consisting of a percentage of the transaction value plus a fixed amount (e.g., 2.9% + $0.30). Transaction fees compensate the PSP for processing, risk, and infrastructure costs.

    Transaction Monitoring

    The ongoing surveillance of payment transactions to detect unusual patterns that may indicate fraud, money laundering, or other financial crimes. Transaction monitoring systems use rules and machine learning to flag suspicious activity in real-time.

    Transaction Risk Analysis (TRA)

    An SCA exemption mechanism under PSD2 that allows PSPs to skip Strong Customer Authentication for transactions assessed as low-risk based on fraud rates. PSPs must maintain fraud rates below specified thresholds to use TRA exemptions.

    Travel Rule

    A FATF recommendation (also adopted in EU and US regulations) requiring financial institutions and crypto service providers to share originator and beneficiary information when transferring funds above certain thresholds, to combat money laundering.

    Crypto Payments Course

    U

    Underwriting

    The risk assessment process an acquirer or PayFac performs before approving a merchant for payment processing. Underwriting evaluates business type, financial health, chargeback history, and regulatory risk to determine approval and pricing.

    UPI (Unified Payments Interface)

    India's real-time mobile payment system that enables instant bank-to-bank transfers through a single mobile application. UPI processes billions of transactions monthly and is the backbone of India's digital payment ecosystem, supporting P2P and merchant payments.

    USDC (USD Coin)

    A fully-backed stablecoin pegged 1:1 to the US Dollar, issued by Circle. USDC is one of the most widely used stablecoins in payment processing due to its regulatory transparency, reserve audits, and availability across multiple blockchains.

    Crypto Payments Course

    USDT (Tether)

    The largest stablecoin by market capitalization, pegged to the US Dollar and issued by Tether Limited. USDT is widely used in trading, cross-border payments, and as a settlement currency in crypto commerce, though it has faced scrutiny over reserve transparency.

    V

    Velocity Check

    A fraud prevention rule that monitors the frequency and volume of transactions from a single card, device, IP address, or account within a defined time period. Velocity checks help detect automated attacks like card testing and account takeover attempts.

    Verification

    The process of confirming the authenticity of a payment method or the identity of a payer. Verification methods include AVS, CVV checks, 3D Secure, micro-deposits for bank accounts, and KYC document checks for merchants.

    Verified by Visa

    Visa's implementation of the 3D Secure authentication protocol, now operating under the Visa Secure brand for 3DS2. It provides an additional identity verification step for online transactions, enabling liability shift from merchant to issuer for authenticated payments.

    Virtual Card

    A digitally generated card number that can be used for online transactions without a physical card. Virtual cards are often single-use or merchant-locked, making them ideal for B2B payments, employee expenses, and fraud reduction.

    Virtual IBAN

    A bank account number that is linked to a physical bank account but can be uniquely assigned to a customer, transaction, or entity for reconciliation purposes. Virtual IBANs simplify payment matching for platforms that receive high volumes of bank transfers.

    Void

    The cancellation of a payment transaction before it has been settled. Unlike a refund, a void prevents the funds from being captured, meaning no money actually moves. Voids are only possible within the authorization window.

    W

    Wallet Address

    A string of alphanumeric characters derived from the public key that serves as the destination for cryptocurrency transfers. Each blockchain has its own address format (e.g., Bitcoin addresses start with 1, 3, or bc1; Ethereum addresses start with 0x).

    Webhook

    An HTTP callback that a PSP sends to a merchant's server to notify it of payment events (e.g., successful payment, refund, chargeback). Webhooks enable real-time event-driven payment processing and are essential for reliable payment integrations.

    WeChat Pay

    A mobile payment service integrated into the WeChat super-app by Tencent. WeChat Pay is one of the two dominant payment methods in China, enabling QR code payments, in-app purchases, peer-to-peer transfers, and bill payments.

    Wire Transfer

    An electronic transfer of funds between banks, typically used for high-value or international payments. Wire transfers are processed through systems like SWIFT (international) or Fedwire (US domestic) and are usually irrevocable once sent.

    Wrapped Token

    A token on one blockchain that represents an asset from another blockchain. For example, Wrapped Bitcoin (WBTC) is an ERC-20 token on Ethereum pegged 1:1 to Bitcoin. Wrapped tokens enable cross-chain asset usage in DeFi and payments.

    Y

    Yield

    The return earned on cryptocurrency holdings through staking, lending, or providing liquidity in DeFi protocols. Yield is typically expressed as an annual percentage rate (APR) or annual percentage yield (APY) and varies based on protocol risk and market conditions.

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