Why GTM makes form tracking hard
In theory, tracking a form submission in GTM is straightforward: create a tag, set a form submission trigger, publish. In practice, modern forms rarely submit in a way GTM's built-in trigger recognises.
AJAX forms, React forms, multi-step forms, popup forms — they all submit data via JavaScript without a traditional form post. GTM's "Form Submission" trigger doesn't fire. You end up configuring custom events, data layer pushes, or click triggers that approximate form submission but don't match it exactly.
Then someone updates the form and the trigger breaks. Silently.
The bigger problem: spam
Even when GTM tracks form submissions correctly, it counts every submission as a conversion. Spam bots, competitors, salespeople pitching their services, job seekers — all counted as wins. Smart Bidding optimises for whoever fills in forms, not for real leads.
Tagless approach
Tagless detects forms automatically — no trigger configuration needed. When someone submits a form, the GCLID is captured and the submission appears in your dashboard.
Here's the key difference: you then qualify which submissions are real leads. Was it a genuine enquiry or a spam bot? A real prospect or a recruiter? Only qualified submissions sync to Google Ads.
Smart Bidding learns what a real form lead looks like, not just what a form submission looks like.