The viewport meta tag controls how a page is displayed on mobile devices. Without it, pages may render incorrectly and fail. In simple terms, the viewport tag tells mobile devices how to scale and display your website. Without it, pages may appear zoomed out, difficult to read, or not properly optimized for mobile users.
What to do: Add a viewport meta tag to the page to ensure it displays correctly on mobile devices.
Where to find: In Shopify, open Online Store → Themes → Edit code → theme.liquid and look inside the <head> section. In most Shopify themes the viewport meta tag only needs to be added once in theme.liquid inside the <head> section.
How to fix: Make sure the following tag is present inside the <head> section:
<meta name="viewport" content="width=device-width, initial-scale=1">
Since theme.liquid is loaded across the entire store, the viewport tag will automatically apply to all pages, including the homepage, products, collections, blogs, and pages. There's no need to add it to individual templates.