Webhooks & Callbacks
The MMG WooCommerce Payment Gateway uses a callback URL (webhook) to receive payment notifications from MMG after a customer completes or fails a payment on the MMG-hosted payment page.
What is the Callback URL?
The callback URL is an endpoint on your WordPress site that MMG calls with an HTTP POST request after every transaction. This is how your WooCommerce store knows whether a payment succeeded or failed — without it, orders stay in "Pending" indefinitely.
The callback URL must be:
- Publicly accessible (not behind a login, VPN, or IP restriction)
- Served over HTTPS
- Registered in your MMG merchant portal
Finding Your Callback URL
-
Go to WordPress Admin > MMG Checkout Control Panel > Dashboard tab.
-
Copy the Callback URL shown — it will look like:
https://yourdomain.com/wc-api/mmg-checkout/random-string -
Contact the MMG support team to have this URL added to your MMG Merchant Portal.
Callback Request Format
MMG sends an HTTP POST to your callback URL with a JSON body. The exact fields are defined by MMG's API — check the MMG merchant portal documentation for the current schema. Key fields include the transaction ID, order reference, payment status, amount, and currency (GYD).
WooCommerce Order Status Mapping
| MMG Payment Status | WooCommerce Order Status |
|---|---|
| Success | Processing |
| Failed | Failed |
| Cancelled | Cancelled |
| Pending | Pending Payment (unchanged) |
Testing Callbacks in Sandbox Mode
In sandbox mode, use a tool like ngrok to expose your local WordPress development site to the internet so MMG can reach your callback URL:
ngrok http 80
Use the https:// ngrok URL as your sandbox callback URL in the MMG sandbox portal.
Viewing Callback Logs
- Go to MMG Checkout Control Panel > Logs tab.
- Each entry shows the timestamp, transaction reference, received payload, and processing result.
- Failed callbacks (e.g., 500 error) show the error and stack trace.
Troubleshooting
See Troubleshooting → Callback URL Not Being Received for common callback problems and fixes.