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Fathom Analytics checker
Check if Fathom Analytics is installed on your site, flag duplicate or render-blocking loads, then confirm visits in your Fathom dashboard.
Scans the page's HTML in seconds. It also reports every other tracking script it finds.
about Fathom Analytics
Why it breaks quietly.
Fathom loads script.js from cdn.usefathom.com and reads your site ID from a data-site attribute. It counts page views and events without cookies.
The script needs that attribute to do anything. A snippet pasted without data-site, or with an ID from another site, loads cleanly and sends nothing useful, so the dashboard simply stays flat.
what the free scan checks
Whether Fathom Analytics is in the page
The scan fetches the page's HTML and matches the vendor's script URL and install snippet.
Whether it blocks rendering
A script tag without async or defer delays the page from painting. Marketing scripts never need to.
Whether it's installed more than once
Duplicate installs usually send every event twice and inflate conversions.
How exposed the page is to blockers
A server-side readiness grade: whether tags load from domains blocklists target, and whether conversions have a server-side path.
It reads the HTML, so tags injected later (inside GTM, for example) don't show up, and it can't see events fire. That's what verification is for.
common failures
How Fathom Analytics goes dark.
data-site is missing or wrong
Without a valid site ID in data-site, the script has nowhere to send page views. An ID copied from another site sends them to that site instead.
Events still use the old goal calls
Fathom moved from goals to events. Older code calling trackGoal with goal IDs should be updated to the current event tracking call.
The script is installed twice
A CMS integration plus a hand-pasted snippet can double page views.
A content security policy blocks the CDN
If your CSP does not allow cdn.usefathom.com, the browser refuses to load the script and logs an error only in the console.
by hand
Check it yourself, step by step.
- 1
Open your Fathom dashboard and check current visitors while you load the site in another browser.
- 2
View the page source and confirm the script tag has a data-site value matching the site ID in Fathom's site settings.
- 3
Open the browser console and check for CSP or blocked-request errors mentioning usefathom.com.
- 4
Trigger a custom event and confirm it appears under Events in the dashboard.
questions
Asked and answered.
Can this check tell me if Fathom events are firing?+
No. It reads served HTML and can see whether the Fathom script is present, duplicated or render-blocking. It cannot see a script loaded at runtime or confirm visits reach Fathom. TracerKit's Verification tier watches real fires and alerts when a tag goes silent.
Why is Fathom not counting my own visits?+
Fathom ignores localhost, and you may have blocked tracking for your browser. Test in a private window on the live site.
Where do I find my Fathom site ID?+
In your Fathom site settings. It goes in the data-site attribute on the script tag.
check other tags
Know Fathom Analytics is firing, every hour of every day.
Verification watches each tag on real traffic and emails you the moment one goes silent. 14-day trial, no card.