GA4 Parameter Validator — Check Event Parameters | Adslytics | Adslytics

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GA4 Parameter Validator

Validate GA4 event parameters against the official spec

How It Works

1

Enter parameter name

Type the GA4 parameter name you want to validate.

2

Enter parameter value

Add the value you plan to send and its data type.

3

Review validation

See if the parameter is reserved, violates length limits, or has type issues.

GA4 Parameter Validator

Why GA4 Parameter Validation Prevents Silent Data Loss

GA4 does not throw errors when you send invalid parameters — it silently drops them. A parameter name that is too long, uses a reserved prefix, or contains an illegal character simply disappears from your GA4 reports with no warning. The GA4 parameter validator catches these issues before your code ships.

GA4 Parameter Rules Every Developer Must Know

  • Name length limit: 40 characters. Parameter names longer than 40 characters are silently truncated or dropped.
  • Value length limit: 100 characters. String values exceeding 100 characters are truncated.
  • Reserved prefixes. Any parameter name starting with firebase_, google_, or ga_ is reserved and will be ignored.
  • Allowed characters. Parameter names can only contain letters, numbers, and underscores.
  • 25 custom parameter limit per event. Standard ecommerce parameters do not count toward this limit.

When to Use Numeric vs String Parameters in GA4

Sending a revenue value as a string ("49.99" instead of 49.99) is a common mistake that breaks purchase attribution, revenue reporting, and ROAS calculations across both GA4 and Google Ads. This validator checks the type of every value you send and flags potential mismatches.

Frequently Asked Questions

GA4 events can have up to 25 custom parameters. Standard parameters like "currency", "value", and "items" do not count toward this limit.
Parameter names must be 40 characters or fewer and can only contain letters, numbers, and underscores, starting with a letter or underscore.
String parameter values can be up to 100 characters. Values over this limit are truncated.
Reserved names include: firebase_conversion, ga_session_id, ga_session_number, and all names starting with "firebase_", "google_", or "ga_".
Yes — GA4 accepts string, number, and boolean values for custom parameters. Only numeric parameters can be used for calculated metrics and revenue reporting.