Google Tag Manager Assistant
We use the tagassistant.google.com to debug events sent from our frontend.
History Changes
You will notice the following when navigation:
The API calls are in order:
// 1 History
dataLayer.push({ event: "gtm.historyChange", .. })
// 2 History
dataLayer.push({ event: "gtm.historyChange-v2", .. })
// 3 History Change
gtag("event", "page_view", {
This is correct behaviour according to Opus 4.5:
┌─────────────────────────────────────────────────────────────────────────┐
│ GTM EVENT → TRIGGER → TAG FLOW │
├─────────────────────────────────────────────────────────────────────────┤
│ │
│ User clicks link │
│ │ │
│ ▼ │
│ React Router: history.pushState() │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ GTM DETECTS THE PUSHSTATE │ │
│ │ │ │
│ │ Pushes TWO events to dataLayer: │ │
│ │ │ │
│ │ #1: gtm.historyChange ← Legacy event (backwards compat) │ │
│ │ #2: gtm.historyChange-v2 ← Current event (triggers use this) │ │
│ │ │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │ │
│ │ These are TRIGGER EVENTS (inputs) │
│ │ They don't send data to GA4 themselves │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ GTM EVALUATES TRIGGERS │ │
│ │ │ │
│ │ "History Change" trigger matches gtm.historyChange-v2 ✓ │ │
│ │ │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │ │
│ ▼ │
│ ┌─────────────────────────────────────────────────────────────────┐ │
│ │ GTM FIRES ASSOCIATED TAGS │ │
│ │ │ │
│ │ #3: GA4 Tag fires → gtag("event", "page_view", {...}) │ │
│ │ │ │
│ │ This is the TAG (output) - actually sends data to GA4 │ │
│ │ │ │
│ └─────────────────────────────────────────────────────────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────────────┘
Why Two History Events?
| Event | Purpose |
|---|---|
gtm.historyChange | Legacy - For old GTM containers/triggers created before v2 |
gtm.historyChange-v2 | Current - The one your "History Change" trigger listens to |
GTM fires both for backwards compatibility. You can ignore gtm.historyChange (#1).
The Key Insight: Events vs Tags
| What | Role | Sends to GA4? |
|---|---|---|
#1 gtm.historyChange | Trigger event (input) | No |
#2 gtm.historyChange-v2 | Trigger event (input) | No |
#3 page_view | Tag execution (output) | Yes ✓ |
#1 and #2 are inputs that GTM uses to decide which tags to fire. #3 is the output - the actual data being sent to GA4.
Your Setup is Working Correctly ✓
The fact that you see:
gtm.historyChange-v2withgtm.triggers: "8"(indicating a trigger matched)page_viewbeing sent to GA4 with correctpage_locationandpage_referrer
Means everything is configured properly. Your SPA navigation is being tracked!