How To: Assess Tag Firing Timing Using Dev Tools "Performance" Tab

Modified on Wed, 12 Jun 2024 at 04:19 PM

To ensure GoogleBot and other crawlers can successfully index your markup, we recommend that Schema App's JavaScript tags run within the first 4 seconds of the page loading. This support document describes how you can use Dev Tools to review tag timing and assess whether adjustments are required for GoogleBot to see and index your markup reliably.


How To: Gather Timing Insights from the Dev Tools Performance Tab

This section describes the process of reviewing tag timing, to assess whether the tags fire within the recommended 4 second time period. 

To open Dev Tools, either right click and select "Inspect" or press CMD/CTRL + Shift + I.

Open Network Conditions and Change your User Agent to GoogleBot

This step is optional but recommended. Change your User Agent within the Network Conditions window in Dev Tools. This support document explains how to change your User Agent.

The Performance Report tab can be found alongside the topmost row of tab options in Dev Tools. This feature does not run by default, so you will need to reload the web page.

Search for [highlightjs]

Open up the Search Dialog box within the Performance Tab (CMD/CTRL + F) and search for [highlightjs]. This should surface information about when Schema App added JSON-LD to the web page. 

To review the exact time the markup was added, hover over the event in the visualizer. A tooltip will appear that notes when this event occurred. In this example, Highlighter template markup was added to the page at the 3.63s mark.

Optional: Filter by Time Frame

By clicking and dragging in the event visualizer, you can create a time-filter that removes results that occur outside the period of interest. It may be useful to set the timeline for the first 4 seconds and look to see whether [highlightjs] receives any matches during that time period. In the example GIF below, note that when the time period is shortened, and matches for [highlightjs] no longer appear.

If the [highlightjs] event happened within the first 4 seconds, this indicates that GoogleBot should be able to index the markup. This is a confirmation that integration should be straightforward with no indexing issues.

However, If the [highlightjs] event happens after the first 4 seconds, this is an indication that tag timing may impact GoogleBot's ability to see and index the JSON-LD Schema App is deploying.

Solutions and Resources 

This section describes the possible solutions for addressing tag timing and some related resources or topics of interest.

Solutions to tags firing late include:

  • Increasing the firing priority for Schema App Integration scripts within your Tag Manager
  • Move the Tag Manager or Integration Scripts to run earlier in the page load process
  • Explore alternative deployment methods (e.g Crawler, JS + Caching)

Resources for Reviewing Tag Timing

To avoid any influence your internet or browser settings may have on tag timing, you may wish to use other tools to test your tag timing. We recommend In this case, you can review the waterfall test and search the page for "schema". You are always welcome to email for further clarification.

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