Glossary
Payment words in plain English. Tap a term for the full explanation.
14 terms
- FPXFinancial Process Exchange, Malaysia's online-banking rail. The customer logs into their bank and approves the payment. Run by PayNet; almost every gateway supports it.
- DuitNow QRThe national interoperable QR standard. One QR code accepts most Malaysian bank apps and e-wallets.
- E-walletStored-value apps like Touch 'n Go eWallet, GrabPay, Boost and ShopeePay. Gateways usually charge a separate e-wallet rate.
- BNPLBuy Now, Pay Later: the customer pays in instalments (Atome, SPayLater, etc.) while you're paid upfront, minus a higher merchant fee.
- MDR / discount rateMerchant Discount Rate: the percentage a gateway keeps per successful transaction. The headline 'fee' in the comparison table.
- Settlement (T+1 / T+2)How many business days after a payment the money lands in your bank account. T+2 means two working days later.
- Webhook / callbackA server-to-server message the gateway sends your backend when a payment's status changes. It's the source of truth for whether you were actually paid, not the browser redirect.
- Signature / checksum verificationA cryptographic stamp (usually HMAC) on each callback proving it really came from the gateway and wasn't tampered with. Always verify it before trusting a webhook.
- Idempotent settlementProcessing the same paid event twice must not deliver the goods twice or double-count revenue. Key off the gateway's reference and ignore repeats.
- Sandbox vs liveSandbox is a test environment with fake money and test keys. Live uses real money and production keys. Build and test in sandbox first; the two have separate credentials.
- TokenisationReplacing card details with a safe token so you can charge again later without ever storing the raw card number.
- Recurring / subscriptionAutomatically charging a saved payment method on a schedule (memberships, SaaS plans, instalments).
- MCPModel Context Protocol: a standard that lets AI coding tools (Claude, Cursor, Codex) talk to a service's API directly. A gateway with an official MCP server is the easiest to wire up with an agent.
- Agent skillA packaged instruction set that teaches an AI coding agent how to integrate a specific gateway correctly and securely. See the setup-* skills in the Build with AI agents section.