Verify that surcharging is legally permitted in the cardholder's jurisdiction; surcharging is prohibited in several US states and countries — check the current list before implementing.
Register your intent to surcharge with Visa and Mastercard at least 30 days before going live; the registration process varies by network but typically involves notifying your acquirer.
At checkout, detect whether the payment method is a credit card (not debit or prepaid) using BIN lookup; surcharges may only be applied to credit cards under network rules.
Cap the surcharge at the lesser of your actual card acceptance cost or the network-specified maximum (currently 3% for Visa and Mastercard in most markets).
Clearly disclose the surcharge amount before the customer completes payment, as a line item in the order summary and on the receipt.
Pass the surcharge amount as a separate field in your authorization request if your gateway supports it, so it is reported correctly to the networks.
Known gotchas
Debit cards, including Visa Debit and Mastercard Debit, cannot be surcharged under network rules even when the transaction runs as a credit transaction; BIN-level credit/debit detection is essential.
Surcharge rules are subject to frequent regulatory changes; the prohibition list changes as US states pass new laws — build your compliance check against a maintained lookup table rather than hardcoding.
Failure to register with the card networks before surcharging can result in fines and potential merchant account termination.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp