Create an authorization for the maximum expected amount (e.g., a product estimate plus a buffer for overages), keeping the capture separate from the authorization.
When the final amount is known, submit a capture request for the actual amount; if less than the authorized amount, the remaining hold is released to the cardholder.
For overcaptures (final amount exceeds the authorized amount), check whether your gateway and acquirer support overcapture and up to what percentage above the original authorization.
If overcapture is not supported, submit an incremental authorization for the additional amount before capturing the combined total.
Reconcile captured amounts against your order management system; flag any mismatch between the captured amount and the order total for manual review.
Void any unused authorizations promptly to release cardholder funds and reduce your authorization-to-capture ratio, which affects interchange rates.
Known gotchas
Mastercard allows overcapture up to a defined percentage for certain MCCs (e.g., restaurants for tips); Visa rules differ and some issuers will reject overcaptures even when network rules permit them.
Partial captures release the remaining authorization hold, but the timing of when the hold is released to the cardholder depends on the issuer, not your acquirer — it can take several days.
Some gateways treat a capture amount of zero as a void; confirm the behavior with your gateway before building logic that relies on zero-amount captures.
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