Processing fees keep climbing. Merchants notice. Partners hear about it.
For ISVs and vertical SaaS platforms, this conversation has become routine. A merchant calls. Their margins are tighter than last quarter. Credit card fees are part of why. They want to know if there is anything you can do about it.
Until recently, the honest answer was usually no. Pass-through fees are pass-through fees. Negotiating them down has limits. Absorbing them yourself means giving up margin you cannot afford to lose.
There is another option, and it has been quietly maturing for years. Surcharging.
What surcharging actually is
A surcharge is a small fee added to a credit card transaction that allows the merchant to recover the cost of accepting that card. The customer who chooses to pay by credit card pays the cost of that choice. The customer who pays by debit, cash, or another method does not.
This is different from cash discounting, which works in the opposite direction. Cash discounting offers a reduced price to customers who pay by methods other than credit card. Both achieve a similar economic outcome. They differ in legal treatment, signage requirements, and how the fee or discount appears on a receipt.
Surcharging used to sit on the edge of the payments industry. Today it is mainstream. Most U.S. states permit it. Card networks have published clear rules. Compliance tooling has matured. For high-volume merchants, it has become one of the most effective ways to protect margin without raising prices on the underlying product or service.
The rules nobody can skip
Surcharging is regulated. The rules are not optional, and partners who skip them put their merchants at risk of fines, processor termination, and reputational damage.
The core rules:
- Surcharges apply to credit cards only. Debit and prepaid cards cannot be surcharged, regardless of how the customer runs the transaction.
- The surcharge cannot exceed 3 percent, or the merchant’s actual cost of acceptance, whichever is lower.
- Merchants must register their intent to surcharge with Mastercard before going live.
- Compliant signage must be displayed at the point of entry and the point of sale.
- The surcharge must be disclosed clearly on the receipt as a separate line item.
- At Constellation Payments, surcharging requires flat-rate pricing. Cost Plus pricing is not currently supported.
These rules exist because the card networks want surcharging to be transparent. The customer should always know, before they pay, that a fee will apply if they choose credit.
How the CSIPay Surcharge Program works
The CSIPay Surcharge Program was built to make compliance straightforward. Two things matter most: it is automated, and it is compliant by default.
Two integration paths are available depending on the partner’s setup.
The first path is a direct API integration. Partners who are PCI compliant and already storing card data can call the BIN lookup endpoint, confirm the card is credit, and append the surcharge amount to the transaction using the feeAmount field. The total amount is calculated automatically and reflected in reconciliation reports.
The second path is PayPageV3, the CSIPay hosted payment page. Partners who are not PCI compliant, or who simply want to avoid handling card data, can use PayPageV3’s dynamic surcharging option. BIN lookup happens natively. The surcharge is applied automatically when the payment method is returned as credit. No card data ever passes through the partner’s servers.
Both paths share the same backend logic. Built-in BIN validation prevents debit and prepaid cards from being surcharged at the system level. Reconciliation is handled monthly. Reporting is transparent and shows the surcharge amount on every receipt and every statement.
For partners, this removes the most common compliance failure points. A merchant cannot accidentally surcharge a debit card. The system will not allow it.
What partners get out of it
The surcharge program is positioned as a merchant solution, but it is also a partner opportunity.
Retention. When a merchant raises processing fees as a concern, partners now have a real answer. That conversation builds trust. It positions the partner as a strategic advisor rather than a passive vendor.
Revenue. The program supports revenue-sharing structures that allow partners to participate in the economics of the program directly. New line of business, with no new product to build.
Differentiation. In a crowded vertical SaaS market, offering a fully compliant surcharge solution is a meaningful capability. Most platforms do not have one. The ones that do tend to win the merchants who care most about margin.
Enablement. The CSIPay Surcharge Program ships with a full library of supporting materials. A Surcharge Addendum. An Attestation Form. Partner positioning and value proposition guides. Signage templates. An integration guide. Partners do not need to become surcharge experts to sell the program. The materials handle most of the work.
Getting started
For partners ready to bring surcharging to their merchants, the path is short:
- Review the Integration Guide to choose the right path (API or PayPageV3).
- Review the Partner Enablement Guide for the merchant onboarding process.
- Confirm the merchant is on flat-rate pricing.
- Have the merchant sign the Surcharge Addendum and Attestation Form.
- Guide the merchant through Mastercard registration.
- Display the required signage at point of entry and point of sale.
Most partners can have a merchant live on the program within a week.
For questions, the CSIPay implementation team is available at [email protected].
The processing rate is the line item every merchant sees. It is not the only cost they pay, and for the right merchant, it does not have to be a cost they absorb. The CSIPay Surcharge Program gives partners a clean, compliant way to put that decision back in the merchant’s hands.