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Safari 2025 update GCLID removal: Store attribution with tracking

BackgroundSolution ApproachResults / ImpactConclusion

Background


Starting September 2025, Safari will introduce changes that could affect how your ad conversions are tracked and reported.

Currently, Safari only removes Google Ads click identifiers (GCLID) in Private Browsing mode. After the update, Safari will remove them during normal browsing as well.

This means:
  • Some ad clicks may not be properly attributed to conversions, especially from Safari users.
  • Smart Bidding may not perform optimally, potentially increasing ad costs
  • Remarketing audiences may shrink, reducing the effectiveness of retargeting campaigns
  • Your reported ROI may appear lower than it actually is
Which Parameters Will Safari Remove
Parameter
Platform
Status
GCLID
Google Ads
❌ Removed
UTM Params
All Platforms
✅ Kept
Why This Matters for Google Ads
GCLID connects ad clicks with conversions. Without it:
  • Conversions may be lost
  • Smart Bidding may not optimize effectively
  • Remarketing lists may shrink
  • Campaign ROI may appear lower than actual
Numbers to Know
  • Safari’s global market share (2024–2025): 17–19%
  • Up to 17–19% of conversions could lose attribution due to GCLID removal
  • Consequences: smaller remarketing audiences, weaker campaign optimization, incomplete reports

Solution Approach

Designed and implemented a backup identifier system using Google Tag Manager (GTM) and 1st-party cookies.

Step 1: Update Tracking URL Suffix in Google Ads

Instead of relying only on gclid, I introduced a backup parameter:

gclid={gclid}&backup_id={gclid}
This ensures: 
  • Chrome/Edge users still pass the native gclid 
  • Safari users lose gclid, but retain backup_id

Step 2: Capture Backup ID in GTM

  • Variable: URL – backup_id

  • Extracts the backup_id parameter from landing page URLs

Step 3: Store Backup ID in a 1st-Party Cookie

  • Tag: New Tag Cookie Creator (GTM template or use JS)
  • Variable: Cookie - custom_gclid
  • Stores the backup_id in a cookie named custom_gclid

Step 4: Send the Correct Identifier on Conversion

On conversion events (e.g., purchase):

  • Variable Logic:

    • If gclid exists → use it

    • Else use custom_gclid from cookie

  • Google Ads Tag Override:

    • page_location is sent with the decorated URL containing the correct identifier

Results / Impact

✅ Conversions remain attributed in Google Ads, even for Safari users
✅ Offline conversion uploads remain reliable
✅ Smart Bidding continues to optimize correctly
✅ Remarketing lists are preserved
✅ Tracking setup is scalable, browser-agnostic, and compliant with privacy updates

Conclusion

By introducing a backup_id + 1st-party cookie + GTM fallback workflow, I ensured that the Safari 2025 update does not break Google Ads attribution.

This solution allows marketing and analytics teams to:
  • Maintain reliable conversion tracking
  • Safeguard Smart Bidding performance
  • Keep remarketing audiences intact
  • Future-proof their setup with minimal complexity