Shopify Theme Detector

Fetch a Shopify store's homepage and read its theme name, version and whether it's from the Shopify Theme Store or custom-built.

How the theme is identified

Shopify storefronts expose a small Shopify.theme JavaScript object on every page, with the theme's name, its internal schema name, its version, and a theme_store_id. A theme_store_id present means the theme is a listed Shopify Theme Store theme (free or paid); no theme_store_id usually means it's a custom build, an agency theme, or one bought outside the Theme Store.

The check also counts third-party scripts loaded on the homepage that aren't served from Shopify's own CDN, since each one is a separate network request the browser has to handle before or while the page renders.

Questions people ask

Can this tell me exactly which theme a competitor bought?

If it's a Shopify Theme Store theme, yes, usually by name. If it's custom-built or from a third-party marketplace, this tool can tell you it isn't a Theme Store theme, but not who built it.

Why does it say the theme is 'custom' when I bought it from the Theme Store?

A theme keeps its Theme Store status only until it's meaningfully customized in a way that changes its theme_store_id association, which some development workflows do. If you're sure it's unmodified, this is worth double-checking with your developer.

Does this access anything private about the store?

No. Everything it reads is sent to every visitor's browser already, the same information your own browser's developer tools would show.

Does a high script count mean the store is slow?

It's one signal, not a full speed test. Run the Shopify speed test tool for a broader (still lite) diagnostic, or PageSpeed Insights for a full Core Web Vitals trace.

Last reviewed 30 September 2026.

Sources: Shopify Help Center: Managing your themes