How Content Impacts Performance

Marketplace is optimized for speed at the platform level, and content decisions still affect real shopper performance.

This page explains the content elements that have the largest impact on load time and responsiveness.

Large images can outweigh the rest of a page’s resources combined.

If a hero image is several megabytes, the browser still has to download that full payload even when the page is served quickly from the edge.

Marketplace does not compress, resize, or re-encode images after upload. Image optimization happens before upload.

A desktop hero image sized for 1920px width is oversized for mobile screens.

Marketplace serves the correct image per device when both are provided.

If a mobile image is not uploaded, mobile devices download the desktop image, which increases LCP and wastes bandwidth.

Video backgrounds have high bandwidth cost during the critical render window.

Key effects:

The video competes with the primary visual content for download bandwidth.
The browser starts downloading the video during page load whether or not the shopper scrolls to it.

Video backgrounds need strict size and duration control to avoid degrading LCP and INP.

Every additional section increases the amount of content the browser must parse and render.

Deep nesting increases DOM complexity and increases the amount of work required before the browser can paint.

Marketplace’s section system performs best with a flat, sequential structure.

GTM container size and tag count directly affect on-device performance.

GTM itself is not the limiting factor.

What impacts performance:

Even with script deferral, a container with many active tags can degrade Time to Interactive and Interaction to Next Paint.