What This Rule Detects

Detects when Reddit's click ID parameter (rdt_cid) appears without matching UTM parameters. GA4 does NOT natively recognize rdt_cid, causing paid traffic to be misattributed as referral traffic.

Why It Matters

Reddit ads without UTM parameters show as "reddit.com / referral" in GA4, making them indistinguishable from organic Reddit traffic. You cannot track campaign performance or calculate ROI.

Required Setup:

❌ WRONG: yoursite.com?rdt_cid=abc123
✅ CORRECT: yoursite.com?rdt_cid=abc123&utm_source=reddit&utm_medium=paid-social&utm_campaign=askreddit

How to Fix

In Reddit Ads Manager:

1. Go to ad group settings
2. Add URL parameters:
   • utm_source=reddit
   • utm_medium=paid-social or cpc
   • utm_campaign={{campaign_name}}
3. Keep rdt_cid enabled
4. Use BOTH together for proper tracking

Why Both Are Needed:

• rdt_cid = Reddit's conversion tracking
• UTM parameters = GA4 attribution
• Both together = Complete tracking

FAQ

Does Reddit + UTMs create duplicate sessions?

No. This is the correct setup. GA4 uses UTMs for attribution while Reddit uses rdt_cid for its own tracking.

What if I only use rdt_cid?

Traffic appears as "reddit.com / referral" - you lose all campaign attribution in GA4.

External Resources

• Reddit Ads Help Center
• GA4 Traffic Source Dimensions