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Guide 45 · Ecommerce · GA4 + Tag Manager

Check ecommerce in DebugView: debug_mode, the event stream, and what each parameter must read

Checked 11 November 2026 · Verification: reference file checked in Python (figures recomputed from the worked example) · Steps traced to Google's developer docs and Analytics Help, opened 11 November 2026 · 5-minute read

Standard reports take about 24 hours, so the same-day check for ecommerce is DebugView: turn on debug_mode, trigger each event, and read its parameters and items before anything is published.

Expected signal

After step 3, DebugView shows each ecommerce event as you trigger it — view_item, add_to_cart, begin_checkout, purchase — with its parameters and items visible on selection. The worked purchase reads value 30.03, tax 4.90, shipping 5.99, currency USD, transaction_id T_12345_3.

Download the reference: the ecommerce-debugview reference (JSON) (1299 bytes, MD5 cf8e56e7050ee84001f1d80aae8a9817). It holds the event parameters, the worked example, and the recomputed figures.

What you need

  • The Google tag on the site, with debug_mode available. DebugView shows data from devices with debug mode on; the install guide covers the tag itself.
  • Access to the website source code, or Tag Assistant Preview. Debug mode is turned on in the config, or by Preview, which enables it for the session.
  • One worked order to trigger. The worked purchase is Google's tutorial order: three tees at 10.01, value 30.03, tax 4.90, shipping 5.99.

The trace

  1. Turn on debug mode. Add 'debug_mode': true to the config command: gtag('config', 'TAG_ID', { 'debug_mode': true }). Tag Assistant Preview enables debug mode for the session as well. Without it, the events go to the property but do not appear in DebugView.
  2. Open DebugView. In Analytics, go to Admin, then Data display, then DebugView. The report shows realtime data from the website, so events appear as they are triggered. DebugView is the place Google's own purchase tutorial points to for verifying that the data is being collected correctly.
  3. Trigger the events in order and select each one. Walk the shop: view the product, add to cart, begin checkout, purchase. In DebugView, select an event to see the parameters, user properties, and items associated with it. The purchase must read transaction_id T_12345_3, value 30.03, tax 4.90, shipping 5.99, currency USD, and the item with price 10.01 and quantity 3. The value is 10.01 × 3 = 30.03, and the charged total is 30.03 + 4.90 + 5.99 = 40.92.
  4. Check the items array, not just the event name. An event can arrive with the right name and the wrong items: an empty array, a missing quantity, a price as text. Expand the items in DebugView for each event. The purchase tutorial's own example uses transaction_id T_12345_3 for the debug step, a fresh ID so the test does not dedupe against the earlier steps.
  5. Leave debug mode off for real traffic. Debug mode is a testing switch. Once the events check out, remove it from the config, or leave it to Preview, which sets it only for the debug session. Then wait about 24 hours for the same events to appear in the standard reports.

Dead ends

DEAD END — THE REPORT STAYS EMPTY WITH DEBUG MODE OFF. DebugView only shows devices with debug mode on. An empty DebugView after triggering the events usually means debug mode is not on for that device, not that the events are missing. Check the config or use Preview.

DEAD END — THE EVENT NAME IS RIGHT AND THE PARAMETERS ARE WRONG. DebugView lists the event by name first, and the parameters only on selection. A purchase that shows its name but carries value as text, or no currency, looks fine at a glance and fails in the reports. Select the event and read the parameters.

DEAD END — TESTING WITH THE SAME TRANSACTION ID TWICE. Google's tutorial gives the debug step a fresh transaction ID, T_12345_3, because Analytics deduplicates on transaction_id. Testing the same order twice with one ID sends the second test into the dedupe, and the report shows one purchase when two were sent.

End state

DebugView shows every ecommerce event the moment it is triggered, with parameters and items on selection. The worked purchase reads transaction_id T_12345_3, value 30.03 (10.01 × 3), tax 4.90, shipping 5.99, currency USD, for a charged total of 40.92. After the check, debug mode comes off, and the standard reports pick the events up after about 24 hours.

Sources

Checked 11 November 2026. The steps above are the ones in Google's purchase tutorial and the ecommerce developer guide, both opened 11 November 2026. No step was run inside a live Analytics property, because that needs a Google sign-in and this site does not sign in as anyone. The figures were recomputed in Python: 10.01 × 3 = 30.03, and 30.03 + 4.90 + 5.99 = 40.92. The reference file was checked the same way.