The problem
A form submission is a conversion, but out of the box it is invisible to analytics. Modern WordPress form plugins submit over AJAX: the visitor stays on the same URL, no new page loads, and no pageview or event reaches GA4. Your most important non-purchase conversion produces no data at all.
The common workaround, redirecting to a thank-you page and counting pageviews on it, is fragile:
- Anyone who lands on the thank-you URL directly, from a bookmark or a shared link, counts as a conversion.
- Page caching can serve the thank-you page in contexts that never involved a submission.
- A pageview carries no context about which form was submitted or where.
The fix: a real event on the actual submission
The reliable pattern is an event pushed to the data layer at the moment the form plugin confirms a successful submission, using GA4’s standard lead event, generate_lead. In GA4 you then mark generate_lead as a key event, and it becomes a conversion you can attribute, segment and bid against.
GTM Kit wires this for you:
- Contact Form 7 (free, built into GTM Kit): on a successful submission, GTM Kit pushes its
gtmkit.CF7MailSentevent and, when thegenerate_leadengagement event is enabled, the standardgenerate_leadevent in the same moment, with form metadata in the payload. - Gravity Forms (GTM Kit Premium): the same
generate_leadpattern fires on the Gravity Forms confirmation, covering AJAX and non-AJAX submissions. Premium also persists the visitor’s acquisition attribution to the form entry itself, so every lead in your Gravity Forms entries carries the source, medium and campaign that produced it. Your sales follow-up sees where each lead came from, not just that it arrived.
Developers can extend the generate_lead payload with extra fields through the gtmkit_engagement_event_generate_lead_payload filter.
Set it up
- Enable the
generate_leadengagement event in GTM Kit’s settings. - In your GTM container, forward the event to GA4 (the GTM Kit container templates include this mapping).
- In GA4, mark
generate_leadas a key event. - Submit a test form with GTM Preview open and confirm the event fires once, on submission, not on page load.
Related
- Contact Form 7 integration
- Engagement events
- GTM Kit Premium — Gravity Forms tracking with per-lead attribution
Run a Tracking Health Check to see which conversions your current setup captures.