GA4 playground for custom events

test.halfhp.com

Plug in a GA4 Measurement ID, initialize gtag.js, then fire custom events with arbitrary params. Handy for DebugView, Tag Assistant, and event schema testing.

Saved locally in your browser for convenience.
Add one or more key/value pairs without writing JSON.
Waiting for a measurement ID.
Quick notes

After init, open GA4 DebugView and optionally Tag Assistant. If you want richer validation, add recommended params like currency, value, or item arrays.

Tag Assistant: tagassistant.google.com
GA4 DebugView: analytics.google.com