The Account Verification Service (AVS) is a bank-to-bank inquiry service used in South Africa to confirm that a bank account number is valid, active, and belongs to the individual or entity presenting it. AVS checks can verify the account number, the account holder's name, their South African ID or company registration number, and the account type (cheque, savings, transmission). AVS is widely used before initiating EFT debit orders, bulk salary payments, and supplier disbursements to prevent failed transactions, reduce return item fees, and protect against fraudulent banking details.

Check Digit Verification (CDV) is a mathematical validation method applied to South African bank account numbers to confirm they are structurally valid before submission. South African banks use proprietary check-digit algorithms (similar in concept to the Luhn algorithm used for credit cards). CDV does not confirm account ownership — it only validates that the account number format and check digit are mathematically consistent for the stated bank and account type. CDV is typically the first verification step, applied immediately when a debtor submits their banking details, before a full AVS inquiry is made.

CDV (Check Digit Verification) validates the mathematical format of an account number — it confirms the number is structurally plausible for that bank. It is an offline, instant check. AVS (Account Verification Service) is a live bank-to-bank inquiry that confirms the account exists, is active, and belongs to a specific person or entity. Together they form a two-layer defence: CDV filters out obviously wrong account numbers instantly, while AVS confirms ownership and account status. Both are important for businesses running EFT collections or bulk payments.

AVS is not legally mandatory under NPS Act regulations, but PASA scheme rules and best practice strongly recommend it before initiating collections or bulk payments. Most payment service providers and banks include AVS as a standard step in their onboarding flow for new debit order mandates. For high-volume collection businesses, AVS significantly reduces the failed EFT rate, which directly reduces PayInc (BankservAfrica) return item charges and improves cashflow predictability. DebiCheck, which is mandatory for new debit orders, provides its own form of mandate authentication but does not replace AVS for account validity checking.