What do cards do better at the checkout, and what must A2A rebuild?

What cards do better for the payer

A fair comparison starts with the payer, because the payer chooses how to pay.

Credit. A credit card is a loan with a payment attached. An instant payment moves money that is already in the account.
Protection. In the US, a credit cardholder's liability for unauthorised use is capped at $50¹. Transfers from a bank account fall under a weaker regime with tiered liability². Under Regulation Z, a cardholder can dispute a billing error within 60 days of the statement³.
Global acceptance. Visa alone processed $17 trillion of payments and cash in fiscal 2025, in almost every country⁴. Instant schemes such as MIA, RoPay or Pix each serve one domestic market.
Mature fraud tooling, backed by data from across the network. Visa paid $946 million for the AI fraud specialist Featurespace⁴.

The markets where instant payments have gone furthest show that these advantages hold. In India, debit card transactions fell by about two thirds between 2021 and 2025, while credit card transactions rose from 2.2 billion to 5.7 billion⁵. In Brazil, credit card value grew 14.5% in 2025 while debit was flat⁶. Instant payments took over everyday spending from money already in the account. Credit stayed on cards.

What the acquiring package does for the merchant

Cards have a second advantage on the merchant side. A card acquirer sells the checkout as one product: the terminal, the settlement report, refunds, the chargeback process, card-on-file billing and integration with the point-of-sale software. An instant payment scheme moves money between banks, and its job ends there.

A rail can launch and still see little use at the till: fourteen months after launch, Mexico's CoDi had processed about one twenty-eighth of the central bank's target⁷.

An A2A acceptance stack has to rebuild at least four functions:

Merchant onboarding. Someone has to sign the merchant up, classify the business and provide the means to accept payments.
Reconciliation. Each payment has to be matched to an order, a till and a shift, and the day has to close cleanly.
Refunds. On a push rail, a refund is a new payment back to the payer, started by the merchant. Whether refunds are available, and on what terms, depends on the scheme. Stripe, for example, supports refunds on Pix payments for up to 90 days⁸ and on UPI for up to 60⁹.
POS integration. The till software already calls a card terminal and expects answers in a known format.

Regulation is rebuilding payer protection. Verification of Payee became mandatory in the euro area in October 2025¹⁰. UK banks repaid 88% of in-scope scam losses between October 2024 and March 2026¹¹.

How miaPOS rebuilds the merchant side

miaPOS is acceptance software inside the bank's perimeter: your licence, your regulator, your relationship. The bank is the A2A acquirer and holds the merchant relationship. This is how miaPOS covers the four functions.

Onboarding. A merchant with a business account at a partner bank submits one activation request, including one sentence on what the business does. The bank checks the company and the administrator against its own client records, calls the administrator and decides on activation. The bank assigns the MCC, using the merchant's own description. Merchants set up their shops and cashiers themselves in the portal; terminals are created only by the bank.
Reconciliation. Every sale at a terminal belongs to a shift, which the cashier opens and closes, and each closed shift has a Z-report. On MIA, RoPay and SEPA Instant the platform uses ISO 20022 end to end, so payments carry structured data. Online, the merchant's backend receives an RSA-signed callback and verifies it before fulfilling the order. The mechanics are covered in an earlier piece.
Refunds. These work where the rail supports them. The POS API has calls to request a return, list return reasons and check return status. On the Windows CLI, an accepted refund comes back as REFUND_PENDING, so the register checks the status before treating the refund as final.
POS integration. The Windows CLI for cash registers follows the same pattern as card-terminal command-line tools, starting with Ingenico Arcus2. A register that already calls Arcus2 changes the executable path and reads the same output files and return codes. Card CLIs from other vendors that follow the same convention can be added on request. In multi-rail mode the CLI opens MIA and the bank's card terminal at the same time. The payer scans the QR code or inserts the card; the first rail to complete wins, and the other is cancelled automatically. The output names the method that won, and the card payment is still processed by the bank's card acquiring service. On Android terminals, the till app starts a QR payment through an Android Intent. Refunds, shifts and receipts go through the POS API.

The card stack stays where it is. The A2A rail gets its own working parts at the same till, and the payer keeps the choice.

The rail is ready. The checkout is not.

Common questions

Can a merchant accept cards and A2A payments at the same till?

Yes. The card payment goes through the bank's card terminal and card acquiring. The A2A payment goes through the acceptance layer for the instant scheme. With the miaPOS Windows CLI and a compatible card CLI, the register can open both at once and the payer chooses; whichever completes first wins.

Are there chargebacks on instant payments?

Not in the card sense. Once the funds have arrived in the merchant's account, the payment is final: the payer's bank cannot reverse it the way a card chargeback does. Refunds are new payments from the merchant, and whether they are available depends on the scheme. Payer protection comes from scheme rules and regulation, such as name checks in the euro area¹⁰ and reimbursement of scam victims in the UK¹¹.

Who assigns the MCC to a merchant accepting A2A payments?

The merchant's bank, because it creates the terminals and holds the merchant relationship. In miaPOS, the activation request includes the merchant's own one-sentence description of the business, so the bank can classify the terminals correctly.

A2A acquiring with miaPOS

Building instant-payment acceptance with your merchants? See how miaPOS works with banks.

For banks

Sources

Written by Ghenadie Cernei, Founder, Finergy. 29 October 2026.

What do cards do better at the checkout, and what must A2A rebuild?

What cards do better for the payer

What the acquiring package does for the merchant

How miaPOS rebuilds the merchant side

Common questions

Sources

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