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Cover image for Runtime Snapshots #1: Taking a “fine” signup form and making it work
Alechko
Alechko

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Runtime Snapshots #1: Taking a “fine” signup form and making it work

Intro

This post kicks off a short weekly series about real use-cases for runtime DOM snapshots with LLMs.

Each week — a different scenario.

Let’s start with a common situation: a signup form that looks fine in code, but in practice frustrates users.


The problem

At first glance the form looks perfect:

  • clean HTML
  • validation rules in place
  • no console errors

But the numbers disagree. Conversion is low. Users drop halfway or click “Submit” and nothing happens.

Static code inspection isn’t enough here. Code shows structure, not what a person actually sees and experiences.


The experiment

Instead of looking only at HTML, imagine capturing a runtime snapshot of the page.

That snapshot (as JSON) includes:

  • which fields are visible or hidden
  • which are required/invalid
  • computed styles (is the “Submit” disabled?)
  • error messages shown on screen

Now an LLM can be asked:

“What’s blocking the signup, and how would you fix it?”


The findings

The answers are suddenly specific, not vague:

  • a required field is hidden → that’s why “Submit” stays disabled
  • error text is only in red → add inline copy so the issue is obvious
  • password field sits far down → move it higher
  • autocomplete=off makes users retype emails → remove it

The outcome

A handful of small changes like these — reordered fields, clearer error copy, fixing one hidden input — can add up fast.

In one experiment, a signup flow improved by about +8% submissions after just a couple of tweaks.

All because the model saw the real state of the form at runtime, not just static code.


Takeaway

  • Static code = blueprint
  • Runtime snapshot = the real X-ray

Give LLMs that context, and the advice becomes concrete.


👉 Want to try it yourself?

We’ve built a free browser add-on that captures runtime DOM state and exports it as JSON for LLMs.

Install Element to LLM for Chrome & Firefox and start running runtime snapshots today.

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