What is GCLID?
GCLID (Google Click Identifier) is a unique tracking parameter that Google automatically adds to your URLs when someone clicks on your ad. It looks like this:
This ID is the key to Google Ads attribution. It connects the ad click to everything that happens afterward — page views, add-to-carts, and purchases. Without it, Google can't tell which ad, keyword, or campaign drove the conversion.
Why GCLID Matters for Your Ads
Why GCLID Gets Dropped on Shopify
GCLID tracking on Shopify is notoriously fragile. The parameter can get lost at multiple points in the customer journey. Here's what happens:
The Result: "Unattributed" Conversions
When GCLID is lost, Google records the conversion but can't attribute it to a specific ad, keyword, or campaign. You'll see conversions in your account, but the data is useless for optimization.
How to Diagnose the Problem
Before fixing anything, confirm that GCLID is actually the issue. Here's how to test:
Check Google Ads Attribution Reports
Go to Reports → Predefined → Conversions → Conversion action. If you see conversions but the associated keywords/ads show as "(not set)", GCLID isn't passing.
Manual Test with Tag Assistant
Install Google Tag Assistant Chrome extension, then:
Check Browser DevTools
Open DevTools (F12) → Application → Cookies. Look for a _gcl_aw cookie. This is where GCLID should be stored. If it's missing or not persisting to checkout, that's your problem.
Common Causes & Fixes
Fix GCLID issues automatically
ScaleUp's Web Pixel integration ensures click IDs pass through Shopify checkout reliably.
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Cross-Domain Tracking Explained
The most common GCLID issue on Shopify is the cross-domain problem. Here's what you need to understand:
GTM Cross-Domain Limitations
Traditional GTM cross-domain tracking doesn't work well with Shopify's checkout due to sandbox restrictions. Even with linker configured, the _gl parameter often doesn't pass correctly into Shopify's iframe-based checkout.
Safari & ITP Issues
Safari's Intelligent Tracking Prevention (ITP) creates additional challenges for GCLID tracking, especially on iOS devices.
Understanding wbraid & gbraid
You may have noticed parameters like wbraid or gbraid in your URLs. These are Google's privacy-preserving alternatives to GCLID.
Good News
If your tracking setup handles GCLID correctly, it should also handle wbraid and gbraid. Google's tags automatically use whichever parameter is available. The key is ensuring your checkout flow preserves all tracking parameters, not just GCLID.
The Best Solution for Shopify
After dealing with all these issues, here's the most reliable approach for Shopify stores:
ScaleUp: Attribution That Just Works
ScaleUp uses Shopify's Web Pixel API and Enhanced Conversions to maintain accurate attribution even when GCLID can't be passed traditionally. No GTM configuration needed.
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Sources
Stop Losing Attribution Data
ScaleUp's Web Pixel integration ensures accurate Google Ads attribution without the GCLID headaches. Set up in 5 minutes.
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Written by Jamie Scott
Founder & CEO, ScaleUp
Jamie has spent years debugging Google Ads tracking issues for Shopify merchants and built ScaleUp to solve these problems automatically.
Helped 2,000+ Shopify merchants improve ROAS
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