Reading tag firing order
The Timeline tab plots each tool's behavior over time, measured from the moment the page started loading. Use it to investigate why a particular tag is slow, or why it doesn't fire at all. This is a Pro-only feature.
Starting a measurement
Click "🔄 Reload page to measure" to reload the page and start recording from that instant. The visible range can be switched between "10 seconds / 30 seconds / Full."
Three kinds of markers
- □ Script load: The moment a
<script>tag was inserted into the page - ○ Request fired: The moment a request to that tool occurred
- ◇ Variable appeared: The moment a global variable like
dataLayerwas first created
Clicking a marker scrolls automatically to the matching row in the "Event list" below and briefly highlights it.
Script load results
Each "Script load" row in the event list shows whether the load actually succeeded (✅ success / 🚫 blocked or failed). "Request fired" only detects that a request occurred — it can't tell you whether that request was actually blocked. Check the Chrome DevTools Network tab if you need certainty there.