Form Start Event (GA4)

In GA4, form_start is an enhanced measurement event sent when a user first interacts with a form during a session, if form interaction measurement is enabled and the form implementation is detectable. The related form_submit event is sent when the form is submitted; neither event alone proves that a business received a valid inquiry or that the server accepted the submission. A plumbing company might compare form starts with form submits to spot friction, then separately check successful form deliveries and qualified leads. Some custom, embedded, or third-party forms may not produce the expected enhanced measurement events. Verify the actual events and form_id or form_name values in the property before interpreting drop-off, and avoid counting form starts as conversions without a deliberate measurement definition.