MetForm → n8n Webhook Bridge

A lightweight WordPress plugin that connects MetForm form submissions directly to n8n workflows in real-time.

✨ Features

• 🔄 Real-time forwarding - Form submissions sent immediately (no queues, no delays)
• 🔐 Secure authentication - Custom secret header validation
• ⚙️ Easy configuration - WordPress admin interface
• 🪵 Comprehensive logging - Track success and failures
• 🛡️ Security first - HTTPS enforcement, input sanitization
• ⚡ Lightweight - Minimal performance impact

📋 Requirements

• WordPress 5.0 or higher
• MetForm plugin (Free or Pro version)
• n8n instance with accessible webhook endpoint
• HTTPS webhook URL (required for security)

🚀 Quick Start

1. Installation

1. Download the plugin files from releases
2. Upload to /wp-content/plugins/metform-n8n-webhook-bridge/
3. Activate the plugin through the WordPress admin

2. WordPress Configuration

1. Go to Settings → MetForm → n8n
2. Fill in the required settings:
   • Webhook URL: Your n8n webhook endpoint (must use HTTPS)
   • Secret: Strong password (minimum 12 characters)
   • Enable Integration: Check to activate
3. Click Save Changes

3. n8n Configuration

In your n8n webhook node, add this validation code:

// Validate webhook secret
const receivedSecret = $request.headers['x-webhook-secret'];
const expectedSecret = 'YOUR_SECRET_HERE'; // Same as WordPress settings

if (receivedSecret !== expectedSecret) {
  $respond.status(401).json({error: 'Invalid secret'});
  return;
}

// Process the form data
const formData = $input.all();
return formData;

📊 Data Structure

The plugin sends this JSON payload to your n8n webhook:

{
  "form_id": "123",
  "fields": {
    "field_name_1": "user_input_1",
    "field_name_2": "user_input_2"
  },
  "timestamp": "2025-09-19T10:30:00+00:00",
  "site_url": "https://yoursite.com"
}

🔧 Configuration Options

🐛 Troubleshooting

Common Issues

✗ "Invalid configuration" error

• Check webhook URL uses HTTPS
• Ensure secret is at least 12 characters
• Verify n8n webhook is accessible

✗ Forms not reaching n8n

• Check WordPress error logs
• Verify webhook URL is correct
• Test webhook endpoint manually
• Ensure MetForm is active

✗ "Unexpected response" error

• Check n8n workflow is active
• Verify secret matches in both systems
• Review n8n execution logs

Logging

Enable WordPress debug logging to see detailed error messages:

// In wp-config.php
define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);

Check logs at: /wp-content/debug.log

🔒 Security

This plugin implements several security measures:

• HTTPS enforcement for webhook URLs
• Secret-based authentication with minimum length requirements
• Input sanitization for all form data
• SSL certificate verification for webhook calls
• No sensitive data storage in plain text

🤝 Contributing

Found a bug or have a feature request? Please create an issue or submit a pull request.

📄 License

This plugin is released under the MIT license.

📞 Support

For support questions:

1. Check the troubleshooting section above
2. Review WordPress and n8n logs
3. Create an issue with detailed information

🔄 Changelog

Version 2.0

• ✨ Added WordPress admin interface
• 🔐 Enhanced security with HTTPS enforcement
• 🪵 Improved logging and error handling
• 🏗️ Refactored to OOP structure
• ✅ Added configuration validation

Version 1.0

• 🎉 Initial release
• 🔄 Basic webhook forwarding
• 🔐 Secret header authentication