Why Mateo captures from a live URL

← All guidesOctober 28, 2026 · 2 min read

There are two ways to read a design: from its pixels, or from the live page. Mateo captures from the live page, and every capture starts with a public URL.

What a screenshot can't tell you

A screenshot is a single frame. Everything in it has to be estimated:

  • Measured values. A screenshot holds no CSS. Colors drift with compression, spacing has to be guessed from pixels, and font sizes and weights are approximations.
  • Motion. Entrance animations, scroll effects and transitions don't exist in a still image.
  • Interactions. Hover and focus states only appear when someone triggers them.
  • Assets. A screenshot flattens logos, icons and images into pixels. You can't hand those to a coding agent as files.
  • Responsive behavior. One screenshot shows one viewport. It can't say how the layout changes on a phone.

An agent building from a screenshot fills every one of those gaps with its defaults.

What the live page gives Mateo

Mateo loads the page in a real browser and captures it as it runs:

  • Screenshots at desktop (five scroll depths) and mobile, as visual ground truth
  • Measured layout: where every section sits
  • Typography, colors, gradients, effects, spacing, radii and shadows as the browser painted them, plus the site's CSS custom properties
  • Assets: the site's real downloadable images, logos, icons and inline SVGs (anything that can't be downloaded is listed by URL)
  • Motion: animation frames and scroll effects
  • Interactions: the hover and focus states Mateo triggered
  • Responsive behavior at desktop (1440) and mobile widths

Screenshots are still part of every capture. They just aren't the only evidence.

What the URL needs

  • It must be a public page. Mateo doesn't capture anything behind a login or paywall.
  • Sites that block automated browsers may fail or come back with Low coverage.
  • Keep the tab open while the capture runs.

When the evidence is thin, the capture says so: its coverage and known gaps tell you what Mateo measured and what your agent should ask you about. See Coverage and known gaps and Getting started.