Case Study: Wise Payment Gateway

The Challenge

Problem

Hosting company receiving bank transfers via Wise needed to manually match payments to WHMCS invoices. With clients across Europe paying in different languages, matching payment references was time-consuming and error-prone.

Manual matching of bank transfers to invoices
Clients use different reference formats (Invoice, Factuur, Rechnung, Facture)
Payments sitting unmatched causing support tickets
No visibility into Wise balance from WHMCS admin
Risk of missed payments or double-matching

The Solution

Solution

Built a complete WHMCS gateway module with Wise webhook integration. Payments are automatically matched to invoices the instant they arrive, with multi-language reference parsing, admin dashboard widget, and manual matching interface for edge cases.

Payment Flow

Client receives invoice

Invoice displays Wise bank details with IBAN and reference number

Client pays via bank transfer

Uses invoice number as payment reference (any language format)

Wise webhook fires instantly

Real-time notification to WHMCS callback endpoint

Reference parsed & matched

Multi-language regex extracts invoice number, verifies amount (±€0.50)

Invoice marked as paid

Automatic payment applied, client notified, transaction logged

Core Features

Instant Webhook Matching

Real-time payment notifications from Wise. Invoices marked paid within seconds of transfer arriving.

Multi-Language Support

Recognizes Invoice, Factuur, Rechnung, Facture and more. Works across European markets.

Admin Dashboard Widget

Shows current Wise EUR balance, reserved amount, and alerts for pending unmatched payments.

Manual Matching Interface

Admin page for edge cases. View unmatched payments, manually assign to invoices, or ignore.

Reference Matching

The plugin recognizes invoice references in multiple formats and languages:

Language	Formats Recognized
English	`Invoice 3530` `INV-3530` `INV3530` `#3530`
Dutch	`Factuur 3530` `Factuur-3530`
German	`Rechnung 3530` `Rechnung-3530`
French	`Facture 3530` `Facture-3530`
Fallback	Any 3+ digit number in the reference string

Technology Stack

PHP 7.4+ WHMCS 8.x Wise API Webhooks MySQL cURL REST API

Results

<5s

Payment to invoice match

0

Manual matching required

4

Languages supported

The gateway eliminates manual payment matching entirely. Bank transfers are automatically reconciled the moment they arrive, reducing support tickets and improving cash flow visibility.

Wise Payment Gateway