How conversion tracking works

4-minute read

JustForms auto-fires conversion events on every analytics platform installed on your page. Zero configuration. Works on any framework.

How it works

On a successful form submission, the embed script:

1. Detects which analytics platforms are loaded on the page (looks for globals: gtag, fbq, dataLayer, etc.)
2. Calls each platform's native conversion API with the right event name + value
3. Fires a custom DOM event justforms:success for your own listeners

Supported platforms (auto-detected)

• Google Analytics 4 — gtag('event', 'generate_lead', { value, currency })
• Meta Pixel (Facebook) — fbq('track', 'Lead', { value, currency })
• Google Tag Manager — pushes { event: 'form_submit', form_id, conversion_value } to dataLayer
• TikTok Pixel — ttq.track('SubmitForm')
• LinkedIn Insight Tag — lintrk('track', { conversion_id })
• Reddit Pixel — rdt('track', 'Lead')
• X (Twitter) Pixel — twq('event', 'tw-Lead')
• Pinterest — pintrk('track', 'lead')
• Microsoft UET (Bing) — uetq.push('event', 'submit_lead_form', ...)
• Plausible — plausible('FormSubmit')

Per-form configuration

In dashboard → form → edit, set:

• GA4 event name — default generate_lead. Change to match your funnel (e.g. contact_submit, demo_request).
• Meta Pixel event — default Lead. Other common values: CompleteRegistration, Contact, Subscribe.
• Conversion value — dollar amount attached to the event (used for ROAS).
• Conversion currency — USD, EUR, GBP, INR, etc.

Custom events + custom code

Listen for the justforms:success DOM event to fire your own tracking:

document.addEventListener('justforms:success', function(e){
  // e.detail.tracking, e.detail.data
  console.log('form submitted', e.detail);

  // Fire your CRM webhook, HubSpot identify, Intercom track, etc.
  window.Intercom?.('trackEvent', 'form-submit', e.detail.data);
});

Verify events are firing

GA4

Open Realtime → Events. Submit a test form. The generate_lead event should appear within 30 seconds.

Meta Pixel

Install the Meta Pixel Helper Chrome extension. Submit a form. The extension shows fired events.

GTM

Open GTM Preview mode. The form_submit event shows in the Tags panel with all data layer values.

All others

Open browser DevTools → Network tab → filter for the pixel's domain (e.g. facebook.net, analytics.tiktok.com). Submit form. A request should fire.