Enhanced Conversions for Facebook Ads is essential in today’s privacy-constrained ad environment. By sending hashed first-party data (email, phone, name) alongside your conversions, you dramatically improve match rates and campaign performance—even with limited browser-based tracking.

🧰 Prerequisites

Item	Requirement
Facebook Pixel & CAPI Access	From Facebook Events Manager
OpenCart 3.x / 4.x	With theme & controller access
Web + Server GTM Installed	GTM snippet in OpenCart header
HTTPS Active	For privacy compliance
Consent Mode (Optional)	For GDPR/CCPA use cases

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🔍 What Are Enhanced Conversions?

Enhanced conversions send hashed customer data (e.g. email, phone) alongside the purchase event to Facebook—either via Pixel or CAPI. This helps Facebook match the event to real users, even if cookies are blocked.

✅ We’ll implement both Web Pixel and Server-Side CAPI for reliable deduplication.

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🛒 Step 1: Capture Purchase + Customer Data in OpenCart

Edit: catalog/controller/checkout/success.php

Add this PHP logic:

$order_id = $this->session->data['order_id'];
$order_info = $this->model_checkout_order->getOrder($order_id);
$products = $this->model_checkout_order->getOrderProducts($order_id);

$email = strtolower(trim($order_info['email']));
$phone = preg_replace('/\D/', '', $order_info['telephone']);

$items = [];
foreach ($products as $product) {
  $items[] = [
    'id' => $product['model'],
    'name' => $product['name'],
    'quantity' => $product['quantity'],
    'price' => $product['price']
  ];
}

$data['fb_enhanced'] = json_encode([
  'event' => 'fb_purchase',
  'email' => hash('sha256', $email),
  'phone' => hash('sha256', $phone),
  'value' => $order_info['total'],
  'currency' => $order_info['currency_code'],
  'transaction_id' => $order_info['order_id'],
  'content_ids' => array_column($items, 'id'),
  'content_type' => 'product',
  'event_id' => uniqid('fb_', true)
]);

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📦 Step 2: Push Data to Web GTM on Success Page

Edit: catalog/view/theme/*/template/checkout/success.twig

{% if fb_enhanced %}
<script>
window.dataLayer = window.dataLayer || [];
dataLayer.push({{ fb_enhanced|raw }});
</script>
{% endif %}

✅ Now GTM has access to all hashed user data + transaction ID.

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🎯 Step 3: Setup Facebook Pixel with Enhanced Conversions (Web GTM)

1. Go to GTM → New Tag → Custom HTML
2. Use the following code for the Purchase Event:

<script>
fbq('track', 'Purchase', {
  value: {{DL - value}},
  currency: '{{DL - currency}}',
  content_ids: {{DL - content_ids}},
  content_type: 'product'
}, {
  eventID: '{{DL - event_id}}'
});

fbq('init', 'YOUR_PIXEL_ID', {
  em: '{{DL - email}}',
  ph: '{{DL - phone}}'
});
</script>

Trigger: Custom Event = fb_purchase

✅ This sends both purchase and enhanced data to Meta.

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🛰️ Step 4: Forward to Server-Side GTM (Optional)

To strengthen tracking even further, forward this data to your Server GTM container:

<script>
fetch('https://gtm.yoursite.com/event', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    event_name: 'Purchase',
    event_id: '{{DL - event_id}}',
    email: '{{DL - email}}',
    phone: '{{DL - phone}}',
    value: '{{DL - value}}',
    currency: '{{DL - currency}}',
    transaction_id: '{{DL - transaction_id}}',
    content_ids: {{DL - content_ids}},
    content_type: 'product',
    action_source: 'website'
  })
});
</script>

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🌐 Step 5: Configure Facebook CAPI Tag in Server-Side GTM

1. Use the Facebook Conversions API Template
2. Tag Settings:

Field	Value
Pixel ID	YOUR_PIXEL_ID
Access Token	From Meta Events Manager
Event Name	Purchase
Event ID	{{event_id}}
Email	{{email}}
Phone	{{phone}}
Value	{{value}}
Currency	{{currency}}
Content IDs	{{content_ids}}
Transaction ID	{{transaction_id}}
Action Source	website

3. Trigger: Event Name equals Purchase

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🔁 Step 6: Deduplicate Client & Server Events

To avoid duplicate events in Meta:

• Use identical event_id for both Pixel and CAPI
• Meta will deduplicate automatically

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🧪 Step 7: QA and Testing

Tool	Purpose
Facebook Test Events Tool	Debug CAPI/Pixels
Server GTM Preview Mode	Verify request payload
Chrome DevTools → Network	Check event firing
Meta Events Manager	Review deduplication success

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✅ Tips for Optimization

Tip	Benefit
SHA256 hash in PHP	More secure than client-side hashing
Use event_id for deduplication	Accurate reporting
Add fbc and fbp cookies in fetch payload	Further matching accuracy
Implement consent checks if needed	Compliant with GDPR/CCPA

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📊 Performance Impact

Metric	Before EC	After EC
Match Rate	~40–60%	80–95%
Conversion Accuracy	Low (cookies only)	High (cookies + hashed PII)
Attribution Lag	Higher	Lower
Retargeting	Unreliable	More precise

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📦 Architecture Overview

[OpenCart Checkout Success]
     ↓
[dataLayer Push → GTM Web]
     ↓                  ↘
[Pixel with EC]      [Forwarded to ssGTM]
                           ↓
                    [Facebook Conversions API]

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