Gateway Fees Addon

Gateway Fees Addon is a free WHMCS module that automatically adds fees — or discounts — to invoices based on the payment method your customer chooses at checkout. Charge a surcharge for costly gateways, or reward cheaper ones with a discount, all handled for you.

What it does

Set a rule per payment gateway and the addon calculates and applies the adjustment when an invoice is created or when the payment method changes. Fixed amounts or percentages are both supported, and a negative value turns a fee into a discount.

Features

• Fixed or percentage-based fees, with negative values for discounts
• Per-gateway toggles and an admin dashboard with overview statistics
• Minimum invoice thresholds and maximum fee caps per gateway
• Client group exemptions
• Optional taxable fees and full activity logging
• One-click recalculation across unpaid invoices
• Fee estimates shown on the Twenty-One checkout theme
• PayPal Payments (PPCP) support (beta) and fully translatable language files

Requirements

Works with WHMCS 8.x and 9.x on PHP 8.1 or newer. Open source under the MIT license, with documentation on GitHub. Free to download.