Heatmaps and session recordings are genuinely useful, and the case against them is not that they're inaccurate. It's that they answer a different question than the one most people buy them for.
They give you data. What most teams need is a decision.
What heatmaps do well
Show you where attention lands, and where it doesn't. A CTA nobody scrolls to is visible immediately.
Reveal the unexpected: dead clicks on a non-clickable element, rage clicks on a broken button, a dropdown nobody opens.
Provide the qualitative texture that numbers strip out. Watching five people struggle with your address field is more persuasive to a team than any chart.
Where heatmaps leave you
They don't rank. A heatmap of a page shows several interesting things and no order among them. You still have to decide which one costs you the most, and you decide it with your gut.
They don't span the funnel. A heatmap describes one page. Your biggest leak is at a transition between pages, and no single-page visualization contains it.
They don't tell you whether a fix worked. After you change something, you get a different heatmap. Different isn't better, and neither picture contains the counterfactual.
They scale badly with attention. Watching recordings is a genuine cost, borne by a person, forever. Ten thousand sessions is not a research method; it's a way to spend a week.
The different job
The job most teams actually want done is: what is costing me the most, what should I change first, and did it work?
That requires three things a heatmap doesn't provide. A repeatable measure, so a number that moves means the site moved. A ranking rule, so the biggest issue is identified rather than presented among equals. And measurement at the step you changed, so a fix can be credited or ruled out.
None of that makes heatmaps bad. It means they're an instrument, not a method.
Use them together, in order
Diagnose first: find the transition that loses the most people, and identify the largest structural friction on that page.
Then reach for a heatmap or a recording when you need to know why — when the numbers say people leave a page and you cannot see what stops them.
That order matters. Opening a heatmap first is how teams end up optimizing a page that was never the problem.
What Defrixa does and doesn't do
Defrixa scores a page deterministically, ranks the friction it finds, and names one fix. With the snippet installed, it identifies the step that loses the most visitors and measures whether a change moved that step.
It is not a heatmap tool, and it doesn't replace watching a real person struggle with your form. Different instruments; different questions.
Common questions
No. Use them second, when you know which page matters and need to understand why it fails.
Any client-side script adds weight. Whether it's material depends on the implementation and your page's budget — measure it rather than assume.
Only if your biggest leak happens to be on the page you chose to instrument, and only if you can tell severity by looking. Neither is safe to assume.