As modern browsers tighten restrictions on client-side tracking (cookies, ad blockers, ITP), server-side tagging has become critical for accurate conversion tracking. This article guides you step-by-step through setting up Snapchat’s Conversions API (CAPI) using Google Tag Manager Server-Side (sGTM) to track Product Sales events.

🎯 Why Use Snapchat CAPI via Server-Side GTM?

• ✅ Improved Attribution Accuracy
• ✅ Bypass Ad Blockers & Cookie Restrictions
• ✅ First-Party Data Reliability
• ✅ Enhanced Pixel Data Resilience

🧰 Prerequisites

Before we start, ensure you have:

1. Snapchat Ads account
2. Snapchat Pixel ID and Access Token
3. Google Tag Manager Server Container setup
4. Custom backend (Node.js, Python, etc.) or Shopify/BigCommerce
5. GTM Web Container already implemented on your site

🔐 Step 1: Generate Snapchat Access Token & Pixel

1. Go to your Snapchat Ads Manager.
2. Navigate to Business Settings > Pixels.
3. Create a Snap Pixel and copy the Pixel ID.
4. Under Business API, generate a CAPI Access Token.

🌐 Step 2: Set Up GTM Server-Side Container

• Go to tagmanager.google.com.
• Create a new Server Container.
• Deploy the server container on App Engine (GCP) or Cloud Run.
• Set up a Custom Domain (e.g., tags.yoursite.com) for the server GTM.

Configure the sGTM container to accept requests from your website’s domain.

⚙️ Step 3: Send Purchase Events to GTM Server Container

Modify your frontend tracking (e.g., GTM Web Container or Shopify Script Editor) to send purchase data to the server.

Here’s a GTM Web Tag example to send data to your sGTM:

fetch('https://tags.yoursite.com/collect', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    event_name: 'Purchase',
    email: 'user@example.com',
    phone: '+1234567890',
    value: 129.99,
    currency: 'USD',
    transaction_id: 'txn_123456789',
    items: [
      {
        item_id: 'sku_001',
        item_name: 'Sneakers',
        quantity: 1,
        price: 129.99
      }
    ]
  })
});

This sends purchase data to the GTM server container for further processing.

📥 Step 4: Create Custom Snapchat CAPI Tag in GTM Server Container

In your Server Container:

🔧 a) Create a New Tag

• Tag Type: Custom HTTP Request
• Name: Snapchat CAPI Purchase

🔧 b) Set Up HTTP Request Code

Here’s an advanced Snapchat CAPI HTTP Request Template:

const pixelId = 'YOUR_PIXEL_ID';
const accessToken = 'YOUR_ACCESS_TOKEN';

const requestBody = {
  pixel_id: pixelId,
  event_type: 'PURCHASE',
  timestamp: new Date().toISOString(),
  event_conversion_type: 'WEB',
  event_tag: 'purchase',
  user: {
    email: data.email ? hash(data.email) : undefined,
    phone: data.phone ? hash(data.phone) : undefined
  },
  properties: {
    currency: data.currency || 'USD',
    price: data.value,
    transaction_id: data.transaction_id,
    items: data.items || []
  }
};

const response = sendHttpRequest('https://tr.snapchat.com/v2/conversion', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${accessToken}`
  },
  body: JSON.stringify(requestBody)
});

return { response: response.body };

function hash(input) {
  return CryptoJS.SHA256(input.trim().toLowerCase()).toString();
}

💡 You may need to include CryptoJS if it’s not built-in, or pre-hash from your site.

🔄 c) Trigger Configuration

Trigger the tag on custom event — e.g., event_name equals Purchase.

🧪 Step 5: Test Snapchat CAPI Integration

• Go to Snapchat Events Manager.
• Choose your Pixel > View Events.
• Use Snap Test Event Code for debugging if needed.
• Test a purchase event via your website.
• Validate if events are arriving from server-side (event source should say CAPI).

🔐 Step 6: Secure & Optimize the Data Layer

• ✅ Hash all user PII using SHA256
• ✅ Use first-party domain in sGTM
• ✅ Set proper CORS headers on sGTM server
• ✅ Log and monitor failed requests

📈 Optional Enhancements

Feature	Benefit
Queue + Retry Logic	Handles Snapchat API timeouts/failures
BigCommerce/Shopify Hooks	Automate server events from purchases
Multi-Event CAPI Tags	Add AddToCart, ViewContent, etc.
Offline Conversion Uploads	Match sales post-click using CSV uploads

📁 Example JSON Payload to Snapchat CAPI

{
  "pixel_id": "abc123",
  "event_type": "PURCHASE",
  "event_conversion_type": "WEB",
  "timestamp": "2025-05-29T16:20:00Z",
  "user": {
    "email": "hashed_email",
    "phone": "hashed_phone"
  },
  "properties": {
    "currency": "USD",
    "price": 199.99,
    "transaction_id": "order_789",
    "items": [
      {
        "item_id": "sku789",
        "item_name": "Wireless Earbuds",
        "quantity": 1,
        "price": 199.99
      }
    ]
  }
}

🔍 Troubleshooting Tips

Problem	Solution
Events not showing in UI	Use test event token or check logs in sGTM
Hashing errors	Ensure SHA256 and lowercase + trimmed input
CORS/403 Errors	Adjust server container headers for custom domains
API Throttling	Monitor limits (200 QPS per account – Snapchat)

 

✅ Summary

Setting up Snapchat CAPI via GTM Server-Side for product sales allows eCommerce stores to track purchase events more reliably, securely, and with better ad optimization.

If you’re investing in Snapchat Ads, CAPI is not optional—it’s essential.