WHMCS Integration

Prerequisites

• WHMCS 8.0+
• A running Pycer instance
• An API key and webhook secret from Developers → API Keys

Installation

Configuration

Enable the gateway

1. Log in to WHMCS Admin
2. Navigate to System Settings → Payment Gateways
3. Click Pycer to activate it

Configure gateway settings

Payment flow

WHMCS invoice created
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Customer clicks "Pay Now"
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Module creates payment via Pycer API
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Customer redirected to Pycer checkout
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Payment completed → Pycer sends webhook
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Callback marks WHMCS invoice as paid

Webhook configuration

1. Your callback URL is:

https://your-whmcs-domain.com/modules/gateways/callback/pycer.php

2. In Pycer, go to Developers → Webhooks and add this URL
3. Select the payment.completed event
4. Copy the webhook signing secret into the WHMCS gateway settings

Test mode

Supported features

• Automatic invoice payment on webhook callback
• Signature verification on every callback
• Test mode toggle
• Multi-currency support
• Refund handling from WHMCS admin

Troubleshooting

1. Go to Billing → Gateway Log and filter by pycer
2. Check that the webhook secret matches exactly in both Pycer and WHMCS
3. Verify your Pycer instance can reach the callback URL
4. Enable debug logging in WHMCS for detailed request/response logs

Related pages

• PHP SDK
• WooCommerce plugin
• Webhooks
• Testing payments