Server-Side for Shopify vs WooCommerce: Technical Specificities (and Pitfalls to Avoid)

In the Swiss e-commerce landscape, two giants share the SME market: Shopify (the all-in-one SaaS) and WooCommerce (the open-source module on WordPress).

For a web agency, managing tracking on these two platforms requires two radically different approaches. What works on one does not work on the other.

Worse, recent updates to Shopify (Checkout Extensibility) have rendered years of "hacks" in the checkout.liquid file obsolete.

At A-Track, we migrate Swiss stores to Server-Side every week. Here is our technical comparison and recommendations to avoid breaking data collection, regardless of your client's CMS.

Shopify: The Locked Fortress (but Robust)

Shopify is a closed environment. It is secure, but it complicates the work of data engineers.

The Big Change: Checkout Extensibility

If you manage Shopify Plus or standard stores, you need to know that access to the checkout code (checkout.liquid) is disappearing.

• The Problem: You can no longer simply paste the GTM script into the checkout code.

• The Solution: You need to use "Customer Events" (Custom Pixels) or third-party applications that use the Shopify API Sandbox.

The A-Track Approach for Shopify

To implement reliable Server-Side Tracking on Shopify, we use the official "Stape Server-Side" application or a manual setup via Custom Pixels.

1. Native DataLayer: The Shopify API now exposes standardized events. No need to code a DataLayer by hand.

2. Webhook: To ensure 100% of conversions, we sometimes configure Webhooks that send the order to the Stape server after payment, regardless of the user's browser.

3. The URL Trap: Shopify uses a secure sandbox domain for third-party scripts. This can block access to 1st party cookies if misconfigured.

WooCommerce: Total Freedom (and Risky)

WooCommerce is a WordPress plugin. You have access to all the PHP code. It’s a developer's paradise, but a maintenance hell.

The A-Track Approach for WooCommerce

Here, there’s no need for an expensive subscription. The solution relies on a free but powerful plugin: GTM4WP (Google Tag Manager for WordPress).

1. GTM4WP Integration: It’s the industry standard. It injects a perfect e-commerce DataLayer for GA4 (items, value, currency, tax) without coding.

2. The Server-Side: We configure GTM to send data to your server container (Stape).

3. The Risk of Conflict: Beware of cache plugins (WP Rocket) or JS optimization that can "break" the loading order of the DataLayer. At A-Track, we always audit plugin compatibility.

The Swiss Nightmare: Payment Gateways (Twint, PostFinance)

This is the common point for both CMSs and the number one cause of tracking losses in Switzerland.

When the customer leaves the site to pay on the Twint app or PostFinance, they do not always return to the site's "Thank You" page.

• Result: The money is collected, but GA4 and Facebook see no sale.

• On Shopify: It’s complex. You need to use server notifications (Webhooks) to validate the sale afterwards.

• On WooCommerce: Some payment plugins (like those from Wallee or Saferpay) offer an option "Send data to GA4 server-side". Otherwise, we need to code it custom.

Technical Comparison for Agencies

The A-Track Expert's Advice

If your client is on Shopify, stop trying to place your GTM scripts 'the old way' in the theme. Migrate to Custom Pixels in the settings. It’s the only sustainable method to track the checkout without being blocked by Shopify's security updates in 2025.