Glossary
This glossary provides definitions for terms used throughout the Paynt developer documentation.
| Term | Definition | Category |
|---|---|---|
| Acquirer | A financial institution that processes credit or debit card payments on behalf of a merchant. | Merchant & Acquirer |
| Activity Launch Mode | Android configuration that determines how activities are launched. The Paynt app uses singleTask launch mode. | Android & App2App |
| ActivityResultLauncher | Android component used to launch an activity and receive a result when it finishes. | Android & App2App |
| AES | Advanced Encryption Standard. Symmetric encryption standard used for securing sensitive payment data. Common key lengths include AES-128, AES-192, and AES-256. | Security & Encryption |
| AID | Application Identifier. Unique identifier used in EMV transactions to identify payment applications on a smart card (e.g., A0000000031010 for Visa). | Data Formats & Standards |
| Android Intent | A software mechanism in Android that enables communication between different app activities. Used in App2App integration to switch between merchant and payment applications. | Android & App2App |
| APACS70 | UK payment messaging standard developed by the Association for Payment Clearing Services, used for electronic payment transactions between financial institutions in the United Kingdom. | Messaging Standards |
| App2App Integration | Application-to-Application integration. Allows a merchant's Android application to communicate with the payment application using Android Intents. | Integration Types |
| Auth Code | Authorization Code. A code returned by the card issuer to confirm that a transaction has been approved. | Merchant & Acquirer |
| Cardholder Receipt | Copy of the transaction receipt given to the customer. | Receipts |
| Cardholder Verification | Process of confirming the identity of the person using a payment card, typically through PIN, signature, or biometric methods. | Cardholder Verification |
| Completion / Capture | Finalizes a pre-authorization by capturing the reserved funds. The completion amount must be less than or equal to the pre-authorization amount. | Payment Transactions |
| Cryptogram | Encrypted data generated during EMV transactions to authenticate the card and transaction, helping prevent fraud. | Security & Encryption |
| CTLS | Contactless. Payment method using NFC technology where the card or device is tapped near the terminal. | Card Technologies |
| Currency Code | ISO 4217 numeric code identifying the currency (e.g., 978 for EUR). | Amount Formatting |
| CVM | Cardholder Verification Method. The method used to verify the cardholder's identity (e.g., PIN, signature, no CVM). | Cardholder Verification |
| ECR | Electronic Cash Register. Point-of-sale system that handles sales transactions and integrates with payment processing terminals. | Terminal & Hardware |
| EMV | Europay, Mastercard, and Visa. Payment technology standard that uses chip-based cards for secure transactions. | Card Technologies |
| EMV Level 1 Certification | Hardware-level certification for payment terminals that validates the physical and electrical characteristics of card readers. | Compliance & Certification |
| EMV Level 2 Certification | Software-level certification that validates the EMV kernel's compliance with EMV specifications. | Compliance & Certification |
| EMV Level 3 Certification | Software-level certification that validates the payment application's compliance with EMV specifications. | Compliance & Certification |
| EMV Tag | Data element in EMV transactions identified by a specific tag number (e.g., 9F02 for transaction amount). | Data Formats & Standards |
| EPOS Integration | Electronic Point of Sale integration. Connects the payment terminal with external devices (POS systems, cash registers) via REST API over local network or internet. | Integration Types |
| External Network Integration | EPOS integration where the terminal receives commands from external networks via a static IP address. | Integration Types |
| Firmware | Low-level software that controls the terminal hardware. Should be kept updated but not arbitrarily upgraded to the latest version. | Terminal Management |
| Gson | A Java library for converting Java objects to JSON and vice versa. Recommended for serializing App2App request/response data. | Android & App2App |
| Host | The payment processor's server that authorizes and processes transactions. Primary and secondary hosts provide redundancy. | Merchant & Acquirer |
| Host Integration | Connection between payment terminals and payment processing networks or systems. | Development |
| HSM | Hardware Security Module. Dedicated cryptographic device that securely generates, stores, and manages digital keys for payment processing. | Security & Encryption |
| ICC | Integrated Chip Card. A payment card with an embedded microchip that stores and processes data securely. | Card Technologies |
| ISO 8583 | International messaging standard for financial transaction card-originated messages between payment systems. | Data Formats & Standards |
| JSON | JavaScript Object Notation. Data format used for App2App request and response payloads. | Data Formats & Standards |
| Local Network Integration | EPOS integration where the terminal and POS system communicate over the same LAN/WiFi network. | Integration Types |
| Logon | Terminal initialization process that establishes communication with the payment host and synchronizes encryption keys. | Reports & Administration |
| MAC | Message Authentication Code. Cryptographic checksum used to verify data integrity. "MAC invalid" errors typically require cycling keys on the terminal. | Reports & Administration |
| Merchant Receipt | Copy of the transaction receipt retained by the merchant for record-keeping. | Receipts |
| MID | Merchant Identifier. Unique identifier assigned to merchants by payment processors for transaction processing and reconciliation. | Merchant & Acquirer |
| Minor Currency Units | Amounts expressed in the smallest unit of currency (cents for EUR). For example, €12.50 is represented as 1250. | Amount Formatting |
| MSR | Magnetic Stripe Reader. Technology that reads data from the magnetic stripe on the back of payment cards. | Card Technologies |
| NEXO | International standard (ISO 20022) for financial services messaging, including retail payment message standards for point-of-sale transactions and terminal management. | Messaging Standards |
| NFC | Near Field Communication. Short-range wireless communication technology used for contactless payments. | Card Technologies |
| P2PE | Point-to-Point Encryption. Security solution that encrypts payment card data from the point of card swipe/dip until it reaches the secure decryption environment. | Security & Encryption |
| PAN | Primary Account Number. The card number, typically masked in responses (e.g., 42**********1234). | Data Formats & Standards |
| Paydroid | Android-based operating system used on PAX payment terminals. | Terminal Management |
| PCI DSS | Payment Card Industry Data Security Standard. Security standard for organizations that handle credit card information, with compliance levels 1-4. | Compliance & Certification |
| PCI PTS | PIN Transaction Security. Security standard for devices that handle PIN-based transactions. | Compliance & Certification |
| PICC | Proximity Integrated Circuit Card. Refers to contactless card transactions in terminal responses. | Card Technologies |
| PIN | Personal Identification Number. A numeric code used to authenticate the cardholder during a transaction. | Cardholder Verification |
| POS | Point of Sale. Location or system where payment transactions are completed between merchants and customers. | Terminal & Hardware |
| Pre-Authorization (Preauth) | Reserves funds on the customer's card without capturing them. Used in hospitality, car rentals, and scenarios where the final amount may differ from the initial reservation. | Payment Transactions |
| PSD / PSD2 | Payment Services Directive. European regulation that governs payment services and payment service providers in the European Economic Area. | Regulatory |
| Push App | TMS function to remotely install or update applications on payment terminals. | Terminal Management |
| Receipt Line Format | Structure defining how receipt text is formatted, including text content, font size (1-9), alignment (L/C/R), and style (N/B). | Receipts |
| Reference ID | An alphanumeric string consisting of 1-36 characters, Special characters are not allowed. Usually shown in 5 groups separated by hyphens, for example, gr3d4fae-9dec-11d0-a763-00a0c91e6bf1. | Payment Transactions |
| Refund | A transaction that returns money to the customer's card. Refunds are standalone transactions and do not require the original transaction's UTI. | Payment Transactions |
| Reversal / Void | Cancels an existing transaction before settlement. Requires the original transaction's UTI and must occur before the end-of-day settlement. | Payment Transactions |
| Sale | An immediate payment transaction that captures funds from the customer's card. The transaction settles in the next batch. | Payment Transactions |
| SDK | Software Development Kit. Collection of software development tools and libraries for creating payment applications. | Development |
| Secure Boot | Security process that ensures only trusted software runs during terminal startup. | Security & Encryption |
| Semantic Versioning | Versioning scheme using three numbers (MAJOR.MINOR.PATCH) to indicate the nature of changes in software releases. | Development |
| Settlement | The process of transferring funds from the cardholder's bank to the merchant's account. Clearing is typically done daily at 01:00 UK time during winter and 02:00 UK time during summer. | Payment Transactions |
| Standalone Mode | Payment application mode that functions independently without requiring integration with external systems. The merchant enters payment amounts manually on the terminal. | Integration Types |
| Tamper-Resistant Design | Security feature in payment terminals that detects and responds to physical tampering attempts. | Security & Encryption |
| Terminal Capabilities | EMV data element that indicates what cardholder verification methods and other features the payment terminal supports. | Terminal & Hardware |
| TID | Terminal Identifier. Unique identifier assigned to a specific payment terminal. | Terminal & Hardware |
| TLS | Transport Layer Security. Cryptographic protocol for securing communications over computer networks, essential for payment data transmission. | Security & Encryption |
| TMS | Terminal Management System. Platform for managing payment terminals, including app installation and configuration (e.g., paxemea.whatspos.com). | Terminal Management |
| Token Service Provider | Entity that provides payment tokenization services, replacing sensitive card data with non-sensitive tokens. | Development |
| Transaction Sequence Counter | EMV data element that tracks the number of transactions performed by a payment application. | Terminal & Hardware |
| UTI | Unique Transaction Identifier. A UUID that uniquely identifies a transaction, required for reversals and completions. The UTI is an alphanumeric string consisting of 1-64 characters. Special characters are not allowed. For example, 000000000001, 000000000002, 000000000003. Each UTI must be a unique value. The UTI can be re-used only when the previous one expires, which currently happens after 3 months, though this is subject to change. | Payment Transactions |
| X-Report | A report showing current transaction totals without resetting them. Used for mid-day reconciliation. | Reports & Administration |
| Z-Report | An end-of-day report that shows transaction totals and resets them. Typically triggers batch settlement. | Reports & Administration |