From ef72526e1dac43547856a336e9953fcc7eb55608 Mon Sep 17 00:00:00 2001
From: Jeff Emmett <jeffemmett@gmail.com>
Date: Wed, 11 Mar 2026 10:30:38 -0700
Subject: [PATCH] feat: add 2% Mollie processing fee surcharge on top of
 payments

Adds a visible processing fee line item so customers cover payment
processing costs instead of having them deducted from the received amount.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 app/api/create-checkout-session/route.ts | 12 +++++++++---
 app/register/page.tsx                    | 12 +++++++++++-
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/app/api/create-checkout-session/route.ts b/app/api/create-checkout-session/route.ts
index 2a9095e..ed436f5 100644
--- a/app/api/create-checkout-session/route.ts
+++ b/app/api/create-checkout-session/route.ts
@@ -13,6 +13,7 @@ function getMollie() {
 
 // Dynamic pricing configuration (in EUR)
 const TICKET_PRICE = 80 // €80 early bird
+const PROCESSING_FEE_PERCENT = 0.02 // 2% to cover Mollie payment processing fees
 
 // Accommodation prices per person for 7 nights
 const ACCOMMODATION_PRICES: Record<string, { label: string; price: number }> = {
@@ -37,18 +38,23 @@ export async function POST(request: NextRequest) {
 
     const registrationData = registrationDataStr ? JSON.parse(registrationDataStr) : null
 
-    // Calculate total
-    let total = TICKET_PRICE
+    // Calculate subtotal
+    let subtotal = TICKET_PRICE
     const descriptionParts = ["CCG 2026 Ticket (€80)"]
 
     if (includeAccommodation) {
       const accom = ACCOMMODATION_PRICES[accommodationType]
       if (accom) {
-        total += accom.price
+        subtotal += accom.price
         descriptionParts.push(`${accom.label} (€${accom.price.toFixed(2)})`)
       }
     }
 
+    // Add processing fee on top
+    const processingFee = Math.round(subtotal * PROCESSING_FEE_PERCENT * 100) / 100
+    const total = subtotal + processingFee
+    descriptionParts.push(`Processing fee (€${processingFee.toFixed(2)})`)
+
     // Build metadata for webhook
     const metadata: Record<string, string> = {}
     if (registrationData) {
diff --git a/app/register/page.tsx b/app/register/page.tsx
index c9bbe6e..33e0a0e 100644
--- a/app/register/page.tsx
+++ b/app/register/page.tsx
@@ -42,9 +42,11 @@ export default function RegisterPage() {
   }
 
   const accommodationPrice = accommodationPrices[accommodationType]?.price ?? 0
-  const totalPrice =
+  const subtotalPrice =
     baseTicketPrice +
     (includeAccommodation ? accommodationPrice : 0)
+  const processingFee = Math.round(subtotalPrice * 0.02 * 100) / 100
+  const totalPrice = subtotalPrice + processingFee
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault()
@@ -290,6 +292,14 @@ export default function RegisterPage() {
                   </p>
                 </div>
 
+                {/* Processing fee */}
+                <div className="flex items-start justify-between py-3">
+                  <div>
+                    <div className="text-sm text-muted-foreground">Payment processing fee (2%)</div>
+                  </div>
+                  <span className="text-sm text-muted-foreground whitespace-nowrap ml-4">€{processingFee.toFixed(2)}</span>
+                </div>
+
                 {/* Total */}
                 <div className="flex justify-between items-center py-4 bg-primary/10 -mx-6 px-6 mt-4">
                   <div>