Secure serverless payment bridge connecting Zoho POS / Books with SumUp Lite and SumUp Solo terminals.
POST /api/checkout/lite — SumUp Lite same-device workflow
POST /api/checkout/solo — SumUp Solo Cloud workflow
POST /api/webhooks/sumup — SumUp webhook listener
GET /pay/[uuid] — Interstitial validation route
GET /pay/callback — Return redirect & visual confirmation