Preview Resizer for Shopify Theme Editor

Resize the mobile preview width in the Shopify theme editor. Drag a slider or pick device presets and see the change live.

The Shopify theme editor locks its mobile preview to one width: 375px. Real customers use everything from an iPhone SE (320px) to a Pro Max (430px) and small tablets. This extension adds the missing width control. What it does: - Drag a slider to set the mobile preview to any width from 120 to 769px - Jump to common device widths with one click: 320 (SE), 375 (iPhone), 430 (Pro Max), 769 (tablet) - Type an exact pixel value when you need precision - The preview updates live while you drag, no refresh needed - Your width is remembered between sessions and shown as a badge on the toolbar icon - One switch turns the override off and restores Shopify's default - Future proof: if Shopify ever renames its preview class, point the extension at the new one in the Advanced section instead of waiting for an update Built for theme developers, agencies and store owners who check spacing, font sizes and image crops across devices before publishing. Notes: - Works on the theme editor (Online Store > Themes > Customize) in mobile preview mode - Changes only what you see in the editor. It never touches your theme code or your live store. - No account, no tracking, no data collection. The only thing stored is your chosen width, saved locally in your browser.