Crypto Glossary

Address Reuse Address reuse occurs when the same blockchain wallet address is used for multiple transactions. In payment processing, address reuse exposes merchant transaction history, weakens privacy, and can cause payment detection errors when multiple customers pay the same address simultaneously. Professional gateways prevent this by generating a unique address per invoice via HD wallet infrastructure. Address Whitelisting Address whitelisting in a payment gateway restricts outgoing withdrawals and settlements to only pre-approved wallet addresses or bank accounts. Even if an attacker gains gateway access, funds cannot be redirected to non-whitelisted addresses. Whitelisting is a critical internal treasury control and standard in enterprise gateway configurations. AML Program AML (Anti-Money Laundering) program is a documented set of policies, procedures, and controls that a payment gateway implements to detect and prevent money laundering and terrorist financing. Required components include customer due diligence, transaction monitoring, sanctions screening, SAR filing, and staff training. Maintaining a compliant AML program is a condition of VASP, CASP licensining. API Security API security in crypto payment gateways includes API key authentication, IP whitelisting, HMAC request signing, rate limiting, and TLS encryption to protect endpoints from unauthorized access. A compromised API key can allow attackers to create fraudulent invoices, redirect payouts, or access sensitive data. Audit Trail An audit trail in crypto payment processing is an immutable, timestamped log of all gateway events — transactions, account access, setting changes, API calls, and compliance actions. Regulators require audit trails to be maintained for a minimum of 5 years. On-chain records provide a cryptographically guaranteed trail for fund movements; off-chain gateway logs document compliance decisions. Auto-Conversion Auto-conversion automatically converts incoming cryptocurrency into the merchant's chosen settlement currency — fiat or stablecoin — at the moment of confirmed payment. It eliminates manual exchange steps and removes exposure to crypto price swings between payment and conversion. Gateways offer configurable conversion ratios such as 100% to fiat or a split between fiat and crypto retention.

B2B Crypto Payment A B2B crypto payment is a transaction between two businesses using cryptocurrency — typically for invoiced goods, international procurement, or intercompany settlement. Crypto offers near-instant cross-border settlement, no wire fees, and blockchain-verifiable payment records. Payment gateways facilitate B2B payments by generating invoices, monitoring payments, and settling in the currency. BIP21 BIP21 is the Bitcoin Improvement Proposal defining the standard URI scheme for Bitcoin payment requests, encoding address, amount, label, and message in a parseable string. Payment gateways use BIP21-compliant URIs to generate Bitcoin QR codes at checkout, ensuring compatibility across all BIP21-supported wallets. It allows customers to scan and pay without manual address entry. Bitcoin Payment A Bitcoin payment is a transaction using BTC sent from a customer's wallet to a merchant's payment address on the Bitcoin blockchain. Payment gateways detect incoming Bitcoin, wait for sufficient confirmations (typically 1–3), and settle the merchant in their chosen currency. Blockchain Analytics Blockchain analytics uses software to trace cryptocurrency origin and movement on public blockchains, identifying connections to illicit wallets, sanctioned entities, or suspicious activity. Leading providers include Chainalysis, Elliptic, and TRM Labs. Regulated crypto payment gateways integrate blockchain analytics for wallet screening, transaction monitoring, and Travel Rule compliance. Blockchain Monitoring Blockchain monitoring is the continuous process by which a payment gateway scans the blockchain for incoming transactions to merchant payment addresses, detects new deposits, tracks confirmation counts, and updates payment status in real time. Fast and reliable blockchain monitoring is a core reliability requirement for production payment processing. Block Time Block time is the average interval between consecutive blocks being added to a blockchain, determining how quickly an incoming payment receives its first confirmation. Bitcoin averages 10 minutes; Ethereum averages 12 seconds; Solana targets 400 milliseconds. For merchants, block time sets the minimum wait for payment confirmation, directly affecting the customer checkout experience. BOLT11 Invoice A BOLT11 invoice is the payment request format used by the Bitcoin Lightning Network, encoding payee node, amount, description, and expiry in a compact string. Merchants display BOLT11 invoices as QR codes, which customers scan with a Lightning wallet to complete near-zero-fee payments. Gateways supporting Lightning generate and monitor BOLT11 invoices automatically.

Callback URL A callback URL is the merchant server endpoint to which a payment gateway sends webhook notifications or IPNs when transaction events occur. Merchants configure callback URLs during integration so that payment confirmations, failures, and updates are automatically routed to their backend. Proper payload validation using gateway-provided signatures prevents fraudulent status injection. CASP A CASP (Crypto-Asset Service Provider) is the EU-specific regulatory category for crypto businesses under MiCA. CASPs must be authorized by a national competent authority in one EU member state and can then passport services across all 27 EU countries. All payment gateways, exchanges, and custodians operating in the EU must qualify as CASPs. Chargeback-Free Payments Chargeback-free payments refer to the inability of crypto transactions to be reversed unilaterally by the payer, unlike card payments where customers can initiate chargebacks for months after purchase. Merchants are protected from fraudulent chargebacks that cost card-accepting businesses an estimated 1–3% of revenue annually. This is one of the most significant commercial advantages of crypto. Cold Wallet A cold wallet is a cryptocurrency wallet that stores private keys in an environment completely disconnected from the internet, making it immune to remote hacking attempts. In crypto payment gateway operations, cold wallets hold the majority of accumulated merchant funds — typically 90–95% of total assets — protecting them from exchange hacks, server breaches, or API exploits. Confirmation Threshold A confirmation threshold is the minimum number of blockchain confirmations a payment gateway requires before considering an incoming payment complete and releasing merchant funds. Bitcoin typically requires 3–6 confirmations; faster chains like Ethereum or Solana may need only 1–12. Higher thresholds increase security; lower thresholds improve checkout speed. Conversion Fee A conversion fee is charged by a payment gateway when converting received cryptocurrency into another currency for merchant settlement. It is expressed as a percentage of the converted amount or built into the spread. Comparing total conversion costs — spread plus fees — is essential when evaluating gateway providers. Correspondent Banking Correspondent banking is the network of relationships between banks facilitating cross-border fiat settlement — the rail crypto payment gateways use to deliver fiat payouts. De-risking by banks has limited gateway access to correspondent banking, making fiat payout infrastructure a key competitive differentiator. Cross-Border Crypto Payment A cross-border crypto payment is a transaction where payer and recipient are in different countries, settled using cryptocurrency to bypass correspondent banking and currency conversion infrastructure. Crypto cross-border payments can settle in minutes at a fraction of international wire transfer costs. Gateways enable this with integrated compliance, FX conversion, and local fiat payout. Crypto Accounting Crypto accounting for merchants involves recording, categorizing, and reporting cryptocurrency receipts, conversions, and settlements in compliance with accounting standards (IFRS or GAAP) and tax regulations. Each crypto receipt typically creates a taxable event requiring the merchant to record fair market value at receipt. Crypto Checkout Widget A crypto checkout widget is an embeddable UI component that merchants integrate directly into their website to accept crypto payments without redirecting customers externally. Widgets handle currency selection, QR code display, transaction monitoring, and payment confirmation in real time. They provide an on-page checkout experience similar to embedded card payment forms. Crypto Invoice A crypto invoice is a payment request generated by a merchant or payment gateway specifying the amount due, accepted cryptocurrencies, the payment address, and an expiry window. Gateways include real-time exchange rate locking to protect merchants from volatility during the payment window. It functions like a traditional invoice but is payable in digital assets directly to a blockchain address. Crypto Merchant Account A crypto merchant account is a business account with a crypto payment gateway allowing a company to receive and manage incoming crypto payments. Unlike traditional merchant accounts tied to acquiring banks, crypto merchant accounts are established directly with a licensed gateway provider after completing KYB verification. They give merchants access to a dashboard, settlement controls, and API. Crypto Payment API A crypto payment API is a set of endpoints allowing developers to programmatically create invoices, generate payment addresses, monitor transaction status, trigger settlements, and retrieve reporting data. APIs enable merchants to build custom checkout experiences, automate reconciliation, and integrate payment data into ERP or CRM systems. Crypto Payment Gateway A crypto payment gateway is a technology service that enables businesses to accept cryptocurrency payments from customers by detecting, verifying, and settling transactions on their behalf. It monitors the blockchain for incoming payments, waits for sufficient confirmations, and delivers funds to the merchant in crypto or converted fiat. Crypto Payment Link A crypto payment link is a shareable URL generated by a payment gateway that directs a customer to a hosted checkout page pre-configured with a specific amount and currency. Merchants can send payment links via email or invoices without integrating a full checkout widget. Payment links typically include an expiry time and auto-generate a unique receiving address per transaction. Crypto Payment Plugin A crypto payment plugin is a pre-built software module integrating a payment gateway's crypto acceptance into e-commerce platforms such as WooCommerce, Shopify, or Magento.. Plugins require minimal technical setup — typically just entering API credentials — and add a crypto payment option to standard checkout flows. They are the fastest path to live crypto acceptance for most online merchants. Crypto Payment Processor A crypto payment processor handles the technical and financial workflow of accepting cryptocurrency — blockchain monitoring, confirmation management, currency conversion, and fund settlement. While 'payment gateway' and 'payment processor' are often used interchangeably, a processor typically refers to the backend engine executing the transaction flow. Crypto Payment Reconciliation Crypto payment reconciliation is the process of matching confirmed blockchain transactions to merchant orders and accounting records to verify all received payments are correctly recorded and settled. Gateways provide exportable transaction reports and webhook notifications to support automated reconciliation with ERP or accounting software. Crypto Refund A crypto refund is a new outgoing transaction initiated by the merchant to return funds to a customer — since crypto transactions cannot be reversed like a card payment chargeback. Payment gateways offer built-in refund functions in the dashboard or API that send a specified amount back to the customer's original payment address. Merchants should establish clear refund policies. Crypto Subscription Billing Crypto subscription billing is a payment model where customers pay for ongoing services in cryptocurrency on a regular schedule. Since crypto is push-only, subscription billing requires customer commitment, smart contract automation, or gateway-managed invoicing workflows. Stablecoins are the preferred asset for subscriptions due to predictable value and no volatility exposure. Crypto Tax Reporting for Merchants Crypto tax reporting for merchants involves declaring income received in cryptocurrency, calculating gains or losses on conversion, and filing required tax authority reports. Most jurisdictions require businesses to report crypto receipts at fair market value on the date of receipt and track any gain or loss on conversion to fiat. Crypto-to-Crypto Settlement Crypto-to-crypto settlement is a model where the customer pays in cryptocurrency and the merchant receives funds in the same or a different cryptocurrency, with no fiat conversion step. Preferred by crypto-native businesses that want to hold digital assets in their treasury, it avoids conversion fees and banking delays but exposes the merchant to volatility. Crypto-to-Fiat Settlement Crypto-to-fiat settlement is a model where the customer pays in cryptocurrency but the merchant receives the equivalent value in fiat after the gateway converts the payment. The gateway typically locks the exchange rate at payment initiation to protect against volatility. It is the preferred settlement model for merchants who want crypto's benefits without holding digital assets. Crypto Treasury Management Crypto treasury management is how a business manages its cryptocurrency holdings from received payments — deciding how much to convert to fiat, how much to hold as stablecoins, and how much to retain as volatile crypto. Payment gateways with treasury tools allow businesses to define allocation percentages and automate the balance between fiat settlement and crypto retention. Currency Conversion Currency conversion in crypto payments exchanges one cryptocurrency for another, or converts crypto to fiat, during the payment settlement flow. Gateways convert at payment detection (real-time), at scheduled batch times (end-of-day), or on demand via merchant instruction. The conversion rate, spread, and timing significantly impact the merchant's actual received revenue. Custodial Wallet A custodial wallet is a cryptocurrency wallet where a third party — typically an exchange, payment gateway, or financial institution — holds the private keys on behalf of the user. The custodian controls access to funds, and the user relies on the custodian's security and solvency. Customer Due Diligence Customer Due Diligence (CDD) involves collecting and verifying information about a customer's identity, business activity, and risk profile before onboarding them to a crypto payment service. Standard CDD includes ID verification, address confirmation, and business documentation. Enhanced Due Diligence (EDD) applies to higher-risk customers and requires deeper investigation and ongoing monitoring.

De-Risking De-risking is the practice of banks closing or restricting accounts of crypto businesses to avoid perceived regulatory risk, regardless of actual compliance. It is a significant challenge for crypto payment gateways that depend on banking relationships for fiat settlement. Gateways with strong AML programs, and proven compliance track records are better positioned. Destination Tag A destination tag is a numeric identifier required when sending XRP or similar cryptocurrencies to a shared wallet address, distinguishing individual recipients. Payment gateways include the destination tag alongside the deposit address in XRP invoices. Missing or incorrect destination tags can cause payments to be irrecoverably misdirected. Double Spend Protection Double spend protection prevents a customer from spending the same cryptocurrency twice — for example paying a merchant and simultaneously sending the same funds elsewhere. Gateways guard against this by requiring multiple confirmations before releasing goods. For zero-confirmation payments, gateways monitor the mempool and detect Replace-by-Fee flags as risk indicators.

Electronic Money Institution An Electronic Money Institution (EMI) is a regulated entity authorized to issue electronic money and provide payment services. Some crypto payment gateways hold EMI licenses to provide electronic money accounts and payment services alongside their crypto services. An EMI license often complements a CASP license for gateways offering both crypto processing and fiat e-money accounts. Enhanced Due Diligence (EDD) Enhanced Due Diligence (EDD) is an elevated level of customer vetting applied to higher-risk clients, going beyond standard KYB/KYC procedures. EDD may include source-of-funds documentation, detailed business history, beneficial ownership analysis, and more frequent ongoing monitoring. It is triggered by PEP status, high-risk jurisdiction, unusual transaction volumes, or adverse media. ERC-20 Payment An ERC-20 payment uses a token built on Ethereum following the ERC-20 standard, including popular assets like USDT, USDC, DAI, and UNI. Payment gateways supporting ERC-20 can accept hundreds of tokens through a single Ethereum integration. Merchants typically accept a curated subset — primarily major stablecoins — to balance diversity with liquidity and compliance manageability. Ethereum Payment An Ethereum payment is a transaction using ETH or ERC-20 tokens (USDC, USDT, DAI) on the Ethereum blockchain. Ethereum's programmability supports complex payment logic via smart contracts. Payment gateways handling Ethereum payments manage gas fee estimation, network congestion monitoring, and Layer 2 routing to optimize settlement cost and speed.

FATF The Financial Action Task Force (FATF) is the international body setting global AML and counter-terrorism financing standards. FATF introduced the VASP concept in 2019 and extended Recommendation 16 (the Travel Rule) to cover crypto transfers. Over 100 jurisdictions have adopted FATF's VASP framework, making it the primary driver of compliance obligations for crypto payment gateways worldwide. Fiat Off-Ramp A fiat off-ramp converts cryptocurrency into fiat currency and transfers proceeds to a bank account or local payment rail. For merchants, the off-ramp is the final step in settlement — converting received crypto into spendable fiat. Settlement speed depends on the rail: SEPA typically settles in 1 business day, SWIFT in 2–5 days. Fiat On-Ramp A fiat on-ramp converts fiat currency (USD, EUR) into cryptocurrency using bank transfers, credit cards, or other payment methods. For merchants and businesses, on-ramps fund crypto wallets or treasury accounts for operational use. Gateway providers increasingly offer integrated on-ramp services alongside payment processing tools. Fiat-To-Crypto Settlement Fiat-to-crypto settlement is a payment model where a customer pays in fiat currency and the merchant receives the equivalent value in cryptocurrency after conversion. Finality Finality in crypto payments is the point at which a transaction is considered irreversible and permanently recorded on the blockchain. Unlike card payments reversible via chargeback for months, crypto transactions become final within minutes to seconds. Transaction finality eliminates chargeback risk for merchants — one of crypto's primary commercial advantages. FinCEN Registration FinCEN registration is the process by which US crypto businesses register as Money Services Businesses with the federal financial intelligence unit. Registered gateways must maintain AML programs, file Currency Transaction Reports for large transactions, submit SARs for suspicious activity, and comply with the Bank Secrecy Act. FX Rate Crypto The FX rate in crypto payment settlement is the exchange rate applied when converting cryptocurrency to fiat during merchant payout. Gateways source FX rates from aggregated market data and apply their spread on top. FX rate transparency is a key factor in evaluating and comparing gateway providers.

Gas Fee Management Gas fee management refers to a gateway's optimization of Ethereum or EVM network fees for payment and settlement transactions. Gateways use real-time gas monitoring to time outgoing transactions during low-fee periods, batch settlements to reduce per-transaction costs, and Layer 2 routing to avoid base layer fees. Effective gas fee management directly reduces merchant settlement costs.

Hash A hash is a fixed-length alphanumeric string generated by a cryptographic function that uniquely represents a block of data — such as a transaction, a block, or a wallet address. In crypto payment processing, the transaction hash (TXID) is the most commonly referenced hash, serving as an immutable receipt that proves a specific payment occurred and was recorded on-chain. HD Crypto Wallet An HD (Hierarchical Deterministic) wallet generates an unlimited sequence of unique child addresses from a single master seed, used by payment gateways to produce a fresh receiving address for every transaction. HD wallets enable serving thousands of merchants and millions of transactions from a secure, auditable key structure. Compromise of one child key does not expose the master key. High-Risk Merchant A high-risk merchant in crypto payment processing presents elevated compliance, fraud, or reputational risk — such as online gaming, forex, supplements, or adult content platforms. High-risk merchants typically face enhanced due diligence during onboarding, higher transaction fees, volume limits, and more frequent transaction monitoring. Hosted Crypto Checkout A hosted crypto checkout is a payment page managed by a payment gateway, to which the merchant redirects customers at purchase. The gateway handles all payment logic, address generation, blockchain monitoring, and confirmation tracking. Merchants avoid security risk by keeping sensitive payment logic off their own servers. Hot and Cold Wallet Split A hot/cold wallet split keeps only a small operational float in internet-connected hot wallets for daily processing while storing the majority of merchant funds in air-gapped cold wallets. Typically 90–95% of assets are held cold and only 5–10% in hot storage. This limits potential losses in a hot wallet security breach. Hot Wallet A hot wallet is a cryptocurrency wallet that remains permanently connected to the internet, used by payment gateways to receive incoming merchant payments and process outgoing settlements in real time. Because hot wallets are always online, they are exposed to a higher risk of hacking compared to cold storage — which is why enterprise-grade gateways limit hot wallet balances to the minimum. HSM HSM (Hardware Security Module) is a dedicated physical device that generates, stores, and manages cryptographic keys in a tamper-resistant environment. Enterprise crypto payment gateways use HSMs to protect private keys used for transaction signing, preventing key extraction even if servers are compromised. HSMs are a compliance best practice for regulated VASPs managing custody of merchant funds.

IPN An IPN (Instant Payment Notification) is an automated message sent by a payment gateway to a merchant's server confirming a payment has been received and processed. IPNs allow merchants to automate order fulfillment without manual payment verification. They typically include the transaction amount, currency, status, and a unique order identifier for reconciliation. IP Whitelisting IP whitelisting restricts API access to requests originating from a pre-approved list of IP addresses. Even if credentials are stolen, requests from unlisted IPs are automatically rejected. IP whitelisting is a recommended security control for production payment integrations with fixed server infrastructure. Irreversibility Irreversibility means that once a cryptocurrency transaction is confirmed on the blockchain, it cannot be canceled, reversed, or recalled by any party. This protects merchants from fraudulent chargebacks but also means mistaken payouts cannot be undone. Payment gateways implement multi-authorization controls and confirmation delays on large outgoing transfers to prevent irreversible errors.

Key Management Service A key management service (KMS) generates, stores, rotates, and controls access to cryptographic private keys used to sign blockchain transactions. Enterprise KMS solutions use HSMs, MPC, or secure cloud enclaves to protect keys at rest and in use. Proper key management is the foundation of gateway security — a compromised key means direct and irreversible loss of all controlled funds. KYB Verification KYB (Know Your Business) is the business identity verification process that regulated crypto payment gateways require merchants to complete before activating their account. KYB verifies the legal entity, registration documents, ownership structure, ultimate beneficial owners (UBOs), and business activity.

Layer 2 Payment A Layer 2 crypto payment is processed on a secondary network built on top of a base blockchain, enabling faster confirmation times and significantly lower fees. Popular Layer 2 payment networks include the Bitcoin Lightning Network and Ethereum Layer 2s (Polygon, Arbitrum, Optimism). Gateways supporting Layer 2 networks enable micro-payments that would be cost-prohibitive on the base layer. Lightning Network Payment Lightning Network payments are near-instant, ultra-low-fee Bitcoin transactions processed through off-chain payment channels. For merchants, Lightning enables sub-second payment confirmation and fees typically under one cent — making it viable for small-value and high-frequency transactions. Gateways supporting Lightning use BOLT11 invoices and manage channel liquidity on behalf of merchants.

Mass Crypto Payout A mass crypto payout allows businesses to send cryptocurrency to hundreds or thousands of recipients in a single operation. Used for affiliate commissions, contractor payments, marketplace payouts, and salary disbursements. APIs or CSV uploads initiate the batch, and the gateway handles address validation, fee calculation, and transaction broadcasting. Merchant ID (MID) A Merchant ID (MID) is a unique identifier assigned to a merchant account upon onboarding, used to associate all API calls, transactions, webhooks, and reports with that specific merchant. It appears in API requests, dashboard URLs, and gateway logs. In white-label or PSP models, each sub-merchant has their own MID within the provider's system. Merchant Onboarding Merchant onboarding is the registration and verification process businesses complete to activate a crypto payment gateway account, including KYB verification, UBO identification, risk assessment, and AML screening. Most regulated gateways complete standard onboarding within 1–5 business days, after which the merchant receives API keys and dashboard access. MFA (Multi-Factor Authentication) MFA (Multi-Factor Authentication) for crypto business accounts requires users to verify identity using at least two independent factors — typically a password plus a TOTP code or hardware security key — before accessing a gateway dashboard or API console. Mandatory MFA prevents account takeover attacks, a primary vector for unauthorized fund withdrawals. MiCA Regulation MiCA (Markets in Crypto-Assets Regulation) is the EU's comprehensive regulatory framework for crypto-asset services, establishing unified licensing, conduct, and consumer protection rules across all 27 EU member states. Crypto payment gateways operating in the EU may need CASP authorization and must comply with applicable MiCA and AML requirements. MPC Wallet An MPC (Multi-Party Computation) wallet splits a private key into shares distributed across different parties or servers, so no single party ever holds the complete key. In crypto payment gateways, MPC replaces traditional private key storage, eliminating single points of compromise. MSB Registration MSB (Money Services Business) registration is required for most US-based crypto payment gateways under the Bank Secrecy Act, administered by FinCEN. Registered MSBs must implement AML programs, file SARs, comply with the Travel Rule, and maintain transaction records. Operating a crypto payment service in the US without required FinCEN registration may violate federal law. Multi-Chain Support Multi-chain support refers to a gateway's ability to process transactions across multiple blockchain networks — Bitcoin, Ethereum, Solana, Tron, BNB Chain — within a single integration. It allows merchants to accept payments from customers using different wallets and assets without separate integrations for each network. Multisig Wallet A multisig wallet requires multiple private key signatures from different servers or authorized approvers before any outgoing transaction is broadcast. Enterprise gateways use multisig (e.g., 2-of-3) to prevent unauthorized fund transfers even if one key is compromised. Multisig also enforces approval controls for large treasury withdrawals.

Network Fee A network fee (blockchain fee or miner fee) is paid to validators or miners for including a transaction in a block. It is separate from the gateway's processing fee and required for every on-chain transaction. Fee amounts fluctuate with network congestion. Gateways absorb fees in their processing margin or charge them separately to merchants. NFC Crypto Payment An NFC (Near Field Communication) crypto payment allows customers to tap an NFC-enabled device or card to a payment terminal to initiate a crypto transaction without manually scanning a QR code. NFC crypto payments are used in physical retail environments. Some hardware wallets and crypto debit cards support NFC tap-to-pay with instant point-of-sale conversion. Node Infrastructure Node infrastructure refers to the blockchain nodes a crypto payment gateway operates or accesses to monitor incoming transactions, broadcast payments, and interact with supported networks. Enterprise-grade gateways run dedicated redundant nodes across multiple hosting regions. Reliable node infrastructure is a prerequisite for fast payment detection and high gateway uptime. Non-Custodial Wallet A non-custodial wallet is a cryptocurrency wallet where the user holds their own private keys without relying on a third party to manage or control access to their funds. No company can freeze, access, or recover funds in a non-custodial wallet — only the private keyholder can authorise transactions.

OFAC Compliance OFAC compliance requires US-based crypto businesses and those serving US customers to screen all transactions against OFAC's Specially Designated Nationals list. Violations can result in penalties from six-figure fines to criminal prosecution. Crypto payment gateways must implement real-time OFAC screening as part of their broader sanctions compliance program. Order ID An Order ID is a unique reference string assigned by a merchant and passed to the payment gateway when creating a payment invoice, linking the crypto transaction to the specific order in the merchant's system. Gateways return the Order ID in all webhooks and reports, making it the primary key for payment-to-order matching. Overpayment An overpayment occurs when a customer sends more than the required amount to a payment address. Gateways handle overpayments differently: some credit the full amount to the merchant, others trigger a partial refund, and some flag the transaction for manual review. Merchants should configure their gateway's overpayment policy to align with their refund procedures.

Partial Crypto Payment A partial crypto payment occurs when a customer pays only a portion of the total invoice amount in a single transaction. Some gateways support multi-transaction invoices where multiple transfers can combine to fulfill one order. Gateways without partial payment support treat the transaction as an underpayment. Passporting Passporting allows a MiCA-authorized CASP or payment institution licensed in one EU member state to offer services across all 27 EU countries without separate national licenses. A gateway authorized in Lithuania can legally serve merchants across the EU. Passporting significantly reduces the regulatory burden for EU-wide crypto payment operations. Payment Confirmation Payment confirmation in crypto refers to a blockchain network validating and including a transaction in a confirmed block. Each subsequent block adds one more confirmation. Payment gateways use confirmation counts to determine when it is safe to release merchant funds, balancing transaction security with settlement speed. Payment Dashboard A crypto payment dashboard is the merchant-facing web interface for managing transactions, viewing settlement reports, configuring payment settings, generating API keys, and monitoring account balances. Dashboards offer real-time transaction feeds, filtering by currency and status, CSV export for accounting, and compliance document management. Payment Expiry Payment expiry is the time limit within which a customer must complete a crypto payment before the gateway's price-locked rate becomes invalid. Standard payment windows range from 10 to 30 minutes. Expired payments that arrive late are typically held pending merchant instruction for refund or manual credit at the new market rate. Payment Gateway Fee Structure A crypto gateway fee structure describes the pricing model used to charge merchants — transaction fees (percentage or flat), conversion spreads, settlement fees, monthly platform fees, and withdrawal fees. Evaluating total cost including hidden spreads is essential when comparing gateway providers. Common models include flat-percentage pricing, tiered volume pricing, custom enterprise agreements. Payment Gateway Uptime Gateway uptime is the percentage of time a crypto payment service is fully operational and able to detect, process, and settle transactions without interruption. 99.9% uptime means approximately 8.7 hours of potential downtime per year. Enterprise merchants should review historical uptime metrics, SLA commitments, and incident response procedures before integrating a gateway. Payment Institution License A payment institution (PI) license is a regulatory authorization allowing a business to provide payment services, including crypto-to-fiat conversion and settlement. Crypto gateways converting crypto to fiat typically require both a CASP/VASP license and a payment institution license. PI licensing imposes capital adequacy, safeguarding, and conduct obligations. Payment Memo A payment memo (also called a payment tag or reference) is a text or numeric identifier attached to transactions on networks like Stellar (XLM) or Cosmos to distinguish individual payments sharing a common deposit address. Gateways generate unique memos per invoice to enable automatic payment matching. Omitting the memo can result in delayed or lost payments requiring manual recovery. Payment URI A payment URI is a standardized string encoding a crypto payment request — including recipient address, amount, and optional label — in a single clickable or scannable link. Payment URIs are embedded in QR codes at checkout, allowing customers to open their wallet with all payment details pre-filled. Each blockchain has its own URI standard (e.g., BIP21 for Bitcoin). Payment Volume Limits Payment volume limits are thresholds set by crypto gateways on the total or individual transaction value a merchant account can process — per transaction, per day, or per month. Limits reflect the merchant's risk profile, compliance level, and KYB verification depth. Merchants can apply for higher limits after establishing a transaction history and providing additional documentation. Payout Schedule A payout schedule defines how frequently a crypto payment gateway transfers accumulated merchant funds to their bank account or wallet — daily, weekly, or when a balance threshold is reached. Merchants configure their schedule in the gateway dashboard to match cash flow and accounting cycles. More frequent payouts reduce treasury risk but may incur additional fees. PEP Screening PEP (Politically Exposed Person) screening identifies whether a customer or beneficial owner holds or held a prominent public function — such as a government official or military officer — posing elevated corruption risk. Crypto payment gateways must screen all customers and UBOs against PEP lists and apply Enhanced Due Diligence to identified PEPs. Point of Sale Crypto A crypto POS payment solution allows brick-and-mortar businesses to accept cryptocurrency in physical retail using a tablet, terminal, or app displaying a QR code or NFC interface. POS crypto solutions integrate with existing cash register software or operate standalone. They typically support instant conversion to local fiat to eliminate volatility risk during in-person payment flows. Price Lock Price lock fixes the cryptocurrency equivalent of a fiat invoice amount at the moment a payment is initiated, protecting the merchant from price movements during the payment window. For example, if a customer owes €100, the gateway calculates the required BTC at the current rate and holds that rate for 10–20 minutes. This ensures the merchant receives exactly the invoiced fiat amount. Processing Fee A processing fee is the charge collected by a crypto payment gateway for handling each transaction — receipt, monitoring, confirmation, and settlement. Typically expressed as a percentage of transaction value (0.2–1.5%), it may be charged alongside or instead of network fees. Volume-based discounts are often available for high-transaction merchants. Prohibited Merchant Categories Prohibited merchant categories are business types that regulated crypto gateways decline to onboard due to high fraud risk, regulatory complexity, or reputational concern — commonly including unlicensed gambling, certain adult content, HYIPs, and weapons dealers. Merchants in gray-area sectors should review a gateway's acceptable use policy before beginning onboarding. Proof of Reserves Proof of reserves is a cryptographic and audit-based process by which a crypto gateway demonstrates it holds sufficient on-chain assets to cover all merchant and user balances. It combines on-chain wallet attestation with a Merkle tree audit allowing individual accounts to verify inclusion without exposing the full dataset. PSP Model A PSP (Payment Service Provider) model aggregates multiple merchants under a single regulatory and banking umbrella, handling compliance, liquidity, and settlement on their behalf. Sub-merchants onboard under the PSP's master CASP/VASP license rather than obtaining their own. This enables faster merchant activation but requires the PSP to conduct thorough KYB for all sub-merchants.

QR Code A QR code crypto payment encodes a payment URI in a scannable image, allowing customers to initiate payments from their mobile wallet app by scanning the code. Payment gateways automatically display QR codes at checkout to simplify the process and reduce address-entry errors. QR codes are standard in both online and in-person crypto payment flows.

Recurring Crypto Payment A recurring crypto payment is a regular scheduled payment for subscriptions, SaaS fees, retainers, or installment plans. Unlike card-based recurring billing, crypto requires the customer to initiate each payment or authorize a smart contract to pull funds automatically. Gateways supporting recurring crypto billing generate new invoices for each cycle and notify customers to pay. Risk Scoring Risk scoring is the automated assessment of a transaction's or customer's risk level based on transaction size, source wallet history, jurisdiction, business type, and behavioral patterns. Gateways use scores to triage compliance decisions: low-risk processes automatically, medium-risk gets enhanced monitoring, high-risk is blocked or escalated for review. Role-Based Access Control Role-based access control (RBAC) restricts which team members can view, initiate, approve, or manage different gateway functions based on their assigned role. RBAC prevents unauthorized fund transfers, reduces insider threat risk, and supports audit trail integrity. MiCA and AML regulations require payment processors to implement proper internal access controls.

Sanctions Screening Sanctions screening automatically checks customers, wallet addresses, and transaction counterparties against official sanctions lists — including OFAC, EU consolidated, and UN lists — before processing payments. Gateways that fail to block sanctioned parties face severe penalties including fines and loss of operating licenses. Sanctions screening must run in real time for every transaction. SAR Filing SAR (Suspicious Activity Report) filing is the mandatory process by which regulated crypto gateways report suspicious transactions to financial intelligence units — FinCEN in the US or national FIUs in the EU. SARs are triggered by unusual transaction patterns, known risk indicators, or manual review findings. Timely SAR filing is a legal obligation under AML regulations in most jurisdictions. Self-Hosted Wallet Compliance Self-hosted wallet compliance refers to verification requirements that regulated gateways must apply when processing transfers to or from non-custodial wallets not controlled by a VASP. SEPA Settlement SEPA (Single Euro Payments Area) settlement transfers fiat funds from a crypto gateway to a merchant's European bank account. Standard SEPA Credit Transfers settle within 1 business day; SEPA Instant settles within seconds. Most EU-licensed crypto gateways offer SEPA as the primary fiat payout method for European merchants. Settlement Period The settlement period is the time between when a customer's crypto payment is confirmed on the blockchain and when the merchant receives funds in their preferred currency. Crypto-to-crypto settlements can be near-instant; fiat settlements depend on the banking rail used — SEPA typically adds 1 business day, SWIFT adds 2–5. Merchants can usually choose daily, weekly, or threshold-based settlement. Shopify Crypto Payment Integration A Shopify crypto payment integration connects a cryptocurrency payment gateway to a Shopify store, allowing merchants to offer crypto at checkout. Integrations can be done via dedicated Shopify apps, API-based custom implementations, or Shopify's payment app partner program. Merchants receive crypto payments through the gateway while Shopify's order management operates normally. Source of Funds Source of funds refers to the origin of the cryptocurrency or fiat money a customer uses in gateway transactions. Regulated processors must verify that funds do not originate from illegal activities, especially for high-value or high-risk transactions. Documentation may include proof of crypto purchase, salary records, or business income evidence. Spread Crypto Payment The spread in crypto payment processing is the difference between the market exchange rate and the rate applied by a gateway during currency conversion at settlement. Gateways typically add a spread of 0.5–2% on top of the mid-market rate as part of their revenue model. A smaller spread means the merchant loses less value in conversion from crypto to fiat. Stablecoin Compliance Stablecoin compliance covers the regulatory and AML requirements applicable when accepting or settling payments in stablecoins like USDT or USDC. Under MiCA, stablecoin issuers and CASPs handling stablecoin transfers face specific obligations including reserve transparency and transfer monitoring. Stablecoin Settlement Stablecoin settlement is a hybrid model where merchants receive accepted crypto payments converted into a stablecoin such as USDT or USDC. It combines the speed of on-chain settlement with price stability similar to fiat. Stablecoin settlement is increasingly popular for cross-border payments where fiat banking rails are slow or expensive. SWIFT Settlement SWIFT settlement refers to international wire transfers used by crypto payment gateways to deliver fiat settlement to merchant bank accounts outside the SEPA zone. SWIFT transfers typically take 2–5 business days and incur correspondent banking fees. Gateways increasingly offer stablecoin payouts or local payment alternatives to bypass slow SWIFT transfers.

Transaction Monitoring Transaction monitoring is the real-time or batch analysis of crypto transactions to detect suspicious patterns, policy violations, or links to illicit activity. It uses rule-based alerts and blockchain analytics to flag transactions for review. Transaction monitoring is a mandatory AML requirement for all regulated crypto payment processors. Travel Rule The Travel Rule requires VASPs and crypto payment gateways to collect and transmit the identity of both sender and recipient alongside cryptocurrency transfers exceeding jurisdictional thresholds. The EU applies it to all CASP-to-CASP transfers regardless of amount; the US applies it above $3,000. Gateways exchange this data with counterparty VASPs through messaging protocols like TRISA or TRP. TRC-20 USDT TRC-20 USDT is the Tether stablecoin issued on the TRON blockchain following TRON's TRC-20 token standard. It is the most commonly used network for USDT payments due to very low transaction fees (often under $1) and fast confirmation times. Payment gateways frequently support TRC-20 USDT for merchant settlements, especially in fee-sensitive markets. TRISA TRISA(Travel Rule Information Sharing Architecture) is an open-source protocol enabling VASPs to securely exchange originator and beneficiary information required by the Travel Rule. Gateways integrated with TRISA automatically verify counterparty VASP status and exchange required data before completing a transfer. TRISA is one of several Travel Rule messaging protocols alongside TRP and OpenVASP. TRON Energy TRON Energy is a network resource consumed when executing smart contract operations on the Tron blockchain, including TRC-20 token transfers such as USDT. Wallets with sufficient Energy (obtained by staking TRX) can transfer USDT at near-zero cost; wallets without Energy burn TRX to cover the execution cost. TRP Protocol TRP (Travel Rule Protocol) is an open standard for sharing Travel Rule compliance data between VASPs, defining the data format and API specifications for transmitting originator and beneficiary information. Gateways implementing TRP can interoperate with a large portion of the VASP ecosystem for automated Travel Rule compliance. TXID (Transaction ID) A TXID (Transaction ID), also called a transaction hash, is the unique alphanumeric string that identifies every confirmed transaction on a blockchain. In crypto payment processing, the TXID is the primary proof that a payment was sent — merchants, gateways, and customers use it to look up transaction status on a blockchain explorer and resolve any payment disputes.

UBO (Ultimate Beneficial Owner) UBO (Ultimate Beneficial Owner) verification identifies and verifies the real individuals who ultimately own or control a business applying for crypto payment services. Under EU AML regulations and MiCA, any person holding 25% or more of a company must be identified with government-issued ID and screened against sanctions and PEP lists. UBO verification is a mandatory component of KYB onboarding. Underpayment An underpayment occurs when a customer sends less cryptocurrency than specified in an invoice — typically due to wallet fees deducted from the sent amount or a manual entry error. Most gateways offer a configurable tolerance threshold within which underpayments are accepted as complete. Amounts outside the tolerance are flagged for merchant review and may require a top-up transaction. Unique Payment Address A unique payment address is a freshly generated blockchain address created by a gateway for each individual transaction, linking a specific customer payment to a specific order. Address uniqueness prevents payment confusion when multiple customers pay simultaneously and is a core feature of all professional crypto payment gateways. USDC Payment A USDC (USD Coin) payment uses USDC, a fully-reserved, audited dollar-pegged stablecoin issued by Circle. USDC is preferred by institutional merchants due to its regulatory transparency and compliance profile. USDC payments settle near-instantly on networks like Solana and Base and are widely used for cross-border B2B payments and treasury management. USDT Payment A USDT (Tether) payment uses USDT, the world's most widely used stablecoin, pegged 1:1 to the US dollar. USDT payments combine crypto speed and global accessibility with dollar price stability — ideal for cross-border merchant settlements, B2B invoicing, and crypto payroll. USDT is available on multiple blockchains including Tron (TRC-20), Ethereum (ERC-20), and Solana.

VASP A VASP (Virtual Asset Service Provider) is any business that exchanges, transfers, safeguards, or facilitates financial services involving virtual assets on behalf of customers, as defined by FATF. Crypto payment gateways, exchanges, custodians, and OTC desks are all VASPs. VASPs must register or obtain licenses from regulatory authorities and implement AML/KYC programs.

Wallet Screening Wallet screening checks a customer's cryptocurrency address against risk databases, sanctions lists, and blockchain analytics before processing a payment. Gateways screen incoming and outgoing wallet addresses to identify links to darknet markets, mixing services, or sanctioned entities. Wallet screening is a core AML control for regulated crypto payment gateways. Webhook A webhook is an HTTP callback that a payment gateway sends to a merchant's server in real time when a payment event occurs — such as a payment being detected, confirmed, or expired. Webhooks eliminate the need to poll the API for status and enable real-time order fulfillment triggers. Merchants configure a webhook URL in gateway settings, and the gateway posts event data automatically. What is Crypto Payroll? Crypto payroll is the practice of paying employees or contractors in cryptocurrency — typically stablecoins or major assets — through a payment gateway or dedicated payroll platform. It enables global salary payments without international wire delays, high fees, or banking restrictions. Gateways supporting crypto payroll handle compliance checks and FX conversion. White-Label Crypto Payment Gateway A white-label crypto payment gateway is a pre-built payment processing platform that a business can rebrand and offer to its own clients under its own name. It allows payment service providers and fintechs to launch crypto acceptance without building blockchain infrastructure from scratch. Solutions typically include full API access, checkout UI, compliance tools, settlement management. WooCommerce Crypto Plugin A WooCommerce crypto plugin adds cryptocurrency checkout to WooCommerce-powered WordPress stores. It auto-generates payment addresses, monitors blockchain confirmations, and updates order status automatically. Installation typically requires only API keys from the chosen gateway provider.

Zero-Confirmation Payment A zero-confirmation (0-conf) payment is accepted immediately after broadcast to the network, before any block confirmation. It provides an instant payment experience but carries a small double-spend risk. Zero-confirmation acceptance is generally only offered for low-value transactions on networks with strong anti-double-spend mempool protections.