Fireshift / Free tools / GA4 event name checker
GA4 event name checker
Paste your event plan. Every event, parameter and user property name is checked against GA4's limits and reserved names, with the Google docs we checked them against.
event: p1, p2=value · event p1 p2 · a pasted gtag('event', …) line.name or name=value.Rules from Google's documentation, checked 5 Nov 2026 (sources below). Nothing you paste leaves this page.
The rules it checks
| Item | Rule |
|---|---|
| Event name | 40 characters max. Starts with a letter. Letters, digits and underscores only, no spaces. Case sensitive. |
| Parameters per event | 25 max. |
| Parameter name | 40 characters max. Can't start with _, firebase_, ga_, google_ or gtag.. |
| Parameter value | 100 characters (500 on GA4 360). page_title 300, page_referrer 420, page_location 1,000. |
| User property | Name 24 characters max, value 36. 25 per property. Can't start with _, firebase_, ga_ or google_. |
| Reserved event names (web) | ad_impression (app only), app_remove, app_store_refund, app_store_subscription_cancel, app_store_subscription_renew, click, error, file_download, first_open, first_visit, form_start, form_submit, in_app_purchase, page_view, scroll, session_start, user_engagement, view_complete, video_progress, video_start, view_search_results. Prefix query_id. |
| Reserved event prefixes | firebase_, google_, ga_. |
| Reserved as custom dimension | Parameters: cid, currency, customer_id, customerid, dclid, gclid, session_id, sessionid, sfmc_id, sid, srsltid, uid, user_id, userid. Plus firebase_conversion, which can't be used at all. |
On top of the hard rules, it warns about capitals (GA4 treats Sign_Up and sign_up as two events), names that differ only by
case, events GA4 already sends through enhanced measurement, and custom names that have a Google recommended event
(signup → sign_up, demo_request → generate_lead). Recommended names get you GA4's built-in reports.
What happens when you break a rule
Nothing warns you when the hit is sent. Depending on the rule, the event or parameter is dropped or the value is cut, and you find out when a report comes up empty or a custom dimension can't be registered. That is why it pays to check names before a release, not after a month of missing data.
Sources, checked 5 Nov 2026: GA4 event collection limits · GA4 event naming rules · Measurement Protocol reference · Firebase Analytics logEvent reference · Recommended events. Google says its reserved lists are not exhaustive and may change.
FAQ
Are GA4 event names case sensitive?
Yes. sign_up and Sign_Up are two events in GA4, each with its own count. The checker flags capitals and names that differ only by case.
How long can a GA4 event name be?
40 characters. Parameter names also 40, parameter values 100 (500 on GA4 360), user property names 24 and values 36.
Can I send my own page_view event?
Google lists page_view as reserved, but documents sending it yourself for single-page apps. Turn off the automatic page view first, or every page is counted twice.
Why is 'form_submit' flagged?
It is an enhanced measurement event that GA4 sends on its own when form interactions are on. A custom form_submit on top double counts and mixes your data with Google's. Name yours after what happened, for example generate_lead.
Does this check my live GA4 property?
No. It checks the names you paste against Google's published rules. To see which events your site actually sends to GA4 and Google Ads, run the free scan.
Want the whole picture, not one container?
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