Payments Glossary

Plain-English explanations of payment terms - gateways, processing, acquirers, QR payments and more, from One Payments.

• Acquirer vs Issuer: What's the Difference?

  Learn the difference between an acquiring bank and an issuing bank, and why both matter every time a card payment is made. Plain-English guide.

• Payment Gateway vs Payment Processor

  Confused by payment gateways and payment processors? Learn how each one works, how they differ, and which your business actually needs to accept card payments.

• QR Code Payments, Explained

  QR code payments let customers pay by scanning a code with their phone. Learn how they work, which regional schemes exist, and when they make sense.

• What Is a Credit Note?

  A credit note is a document that reduces what a customer owes. Learn what credit notes are, when to issue them, and how they differ from refunds and invoices.

• What Is a Payment Gateway?

  A payment gateway connects your checkout to card networks and payment methods. Learn how it works, what it does, and what to look for when choosing one.

• What Is Payment Processing?

  Payment processing is the end-to-end flow that moves money from a customer to your account. Learn how it works, who's involved, and what it costs.

• Merchant Discount Rate: What It Is and What You Actually Pay

  Learn what the merchant discount rate is, how it is calculated, and what Singapore businesses typically pay — with transparent flat-rate pricing from one.ooo.

• What Is a Payment Aggregator? A Plain-English Guide for Businesses

  A payment aggregator lets businesses accept cards under one contract — no individual merchant account needed. How it works and who it suits.

• What Is a Merchant Acquirer? Role in the Payment Chain Explained

  Learn what a merchant acquirer does, how it differs from a payment gateway or card issuer, and how ONE Payments simplifies acceptance for Singapore businesses.

• Interchange Fees Explained: What Every Singapore Merchant Should Know

  Learn what interchange fees are, who sets them, how they fit into your total processing cost (MDR), and how Singapore businesses can manage them effectively.

• What Is a Payment API? A Developer's Guide to Accepting Payments in Code

  A payment API lets your app accept and move money through code, not a hosted form. Here's how it works, what to look for, and how it differs from a gateway.

• What Is a Payment Facilitator (PayFac)? A Plain-English Guide

  A payment facilitator lets a platform onboard its own sub-merchants under one master account. See how a payfac differs from an aggregator, PSP and acquirer.