If you run ads on multiple platforms, you may be dealing with a Meta Pixel, a Google Ads conversion tag, a GA4 tag, and a TikTok Pixel all on the same Shopify store. Each has its own implementation requirements, server-side API, and attribution logic. Understanding how they compare helps you prioritise which to implement first, which to add next, and where each one’s limitations lie.
Meta Pixel + Conversions API
What it does
Tracks user behaviour on your Shopify store and sends event data to Meta for campaign measurement, optimisation, and audience building. The Pixel is the browser-side component; the Conversions API (CAPI) is the server-side component.
Events tracked
PageView, ViewContent, AddToCart, InitiateCheckout, Purchase (and others). The Purchase event with value and currency is essential for ROAS reporting.
Server-side API
Meta Conversions API sends events from your server. Recommended for all stores running Meta Ads. Especially important post-iOS 14 where browser-side pixel data is significantly impacted by App Tracking Transparency.
Attribution
Meta defaults to 7-day click, 1-day view attribution. Often shows significantly more conversions than GA4 last-click because of its view-through attribution window and cross-device matching via Facebook account graph.
Priority for implementation
High — required if you run Facebook or Instagram ads. Without it, Meta campaigns have no conversion data for optimisation.
Google Ads Conversion Tag + Enhanced Conversions
What it does
Tracks conversions from Google Ads clicks (Search, Shopping, Display, YouTube, Performance Max). The conversion tag fires on your thank-you page and sends the conversion back to Google Ads with gclid matching.
Events tracked
Purchase conversion (most important), plus any other conversions you configure (begin_checkout, lead, etc.).
Server-side equivalent
Enhanced Conversions sends hashed customer data (email, phone) alongside the conversion to improve match rate. Can also be implemented server-side via the Google Ads API or via GA4 import.
Attribution
Click-based only (no view-through for Search). 30-day click window by default. Generally more conservative than Meta’s attribution.
Priority for implementation
High — required if you run Google Ads. Smart Bidding cannot function without conversion data. GA4 ecommerce data can be imported into Google Ads as an alternative to a direct conversion tag.
GA4 (Google Analytics 4)
What it does
Tracks all website behaviour and ecommerce events for analytics reporting. Not an ad pixel — primarily used for understanding what users do on your site rather than for ad campaign optimisation.
Events tracked
The full ecommerce event sequence (view_item, add_to_cart, begin_checkout, purchase) plus all other on-site behaviour. Most comprehensive data collection of the three.
Server-side equivalent
GA4 Measurement Protocol allows server-side event sending. Less commonly implemented than Meta CAPI but useful for purchase events that cannot be reliably tracked browser-side.
Attribution
Last-click (default) or data-driven attribution. Most conservative of the three. GA4 is the source of truth for cross-channel comparison because it is not biased toward any single ad platform.
Priority for implementation
High — recommended for all stores regardless of ad spend. GA4 provides the independent view of performance that helps evaluate all other platform-reported data.
TikTok Pixel + Events API
What it does
Tracks conversions from TikTok Ads clicks and impressions. Required for TikTok campaign measurement and audience building.
Events tracked
ViewContent, AddToCart, InitiateCheckout, Purchase. Same structure as Meta with slightly different event naming conventions.
Server-side equivalent
TikTok Events API (server-side). Recommended for stores with significant TikTok Ads spend to improve match quality and capture events missed by the browser pixel.
Attribution
TikTok’s default attribution window is 7-day click, 1-day view. TikTok attribution typically shows higher conversion numbers than GA4 because TikTok includes view-through conversions in its default reports.
Priority for implementation
Required if running TikTok Ads. Lower priority than Meta and Google Ads for stores not yet investing in TikTok.
Which Setup Does Your Store Need?
If you run Meta Ads only: Meta Pixel + CAPI + GA4.
If you run Google Ads only: Google Ads conversion tag + GA4.
If you run both: all three (Meta Pixel + CAPI, Google Ads tag, GA4).
If you also run TikTok: add TikTok Pixel + Events API.
Every store should have GA4 as the independent analytics layer. Ad platform pixels are added based on which platforms you actively advertise on.
Book your free Shopify tracking audit here and we will review your current pixel setup, identify any gaps, and prioritise what needs to be fixed or added.