Why Shopify Store Owners need this
Every app you install on Shopify tends to add something to your storefront: a script, a stylesheet, a widget that loads on every page. Reviews, pop-ups, upsell bars and chat bubbles pile up, and one day the store feels slow and nobody can say which app did it. The same theme and app layer is also where title tags and H1s quietly disappear, and where flat collection URLs and missing meta description templates force you into more apps to fix things. Before you add yet another one, measure what your store actually sends back. The Page Speed & Size Test sends one real request to a URL you choose and reports server response time, HTML download time, HTML weight, compression and caching headers, plus counts of scripts, stylesheets and images found in the markup. That gives Shopify store owners a baseline you can repeat after every app install or removal. It will not run your page in a browser or name the guilty app, but comparing a bloated collection page with a clean one gets you close.
Shopify Store Owners specific guidance
Pick pages that expose the apps
Start with two URLs: a heavy one and a light one. Run a busy product page such as https://yourstore.com/products/linen-shirt, then run a plain page such as https://yourstore.com/pages/contact. Apps that inject code into every product page, like review widgets and upsell bars, show up as more external scripts and stylesheets on the product page than on the contact page. Write down the Resource Breakdown counts and the TTFB for both. Then run each page twice more, because a single run can swing with cache state. The result does not prove which app is responsible, and it does not show anything a visitor's browser loads after the HTML, such as images or script files.
Reading the numbers
Look at TTFB first. Under 200 ms is good, under 600 ms is a warning, and anything slower is flagged bad. A slow TTFB on every page, including the plain ones, points away from your apps and toward caching or network distance. Shopify hosts the storefront, so your own lever there is small, and the useful move is comparing page types. A normal TTFB with a high script and stylesheet count points at the theme and its apps. The tool scores render-blocking files up to 25, images up to 40 and HTML weight up to 1 MB. A pass does not mean the store feels fast on a phone, because no Lighthouse score, LCP, INP or CLS is reported.
What to change, in this order
Work from the cheapest change to the riskiest. In the Shopify admin, open Online Store, then Themes, then Customize, and switch off entries in the App embeds panel for apps you no longer use. Next, uninstall leftovers under Apps in the admin; some apps leave snippet code behind, so open the theme's ... menu, choose Edit code and search theme.liquid for the old app's name. Re-run the same two URLs after each change and compare the script and stylesheet counts. Removing code can also take out the title tag or H1, so check those afterwards with the Meta Tag Analyzer. A lower count does not prove faster real-world loading, only that less is being sent.
Example scenarios
1. Review app on every product page
- Situation
- Illustrative example: a store owner installed a review widget and an upsell bar last month, and product pages now feel slower than the About page.
- Input
https://yourstore.com/products/linen-shirtcompared withhttps://yourstore.com/pages/contact- Reading the result
- The product page might show 14 external scripts and 6 stylesheets (20 render-blocking files), while the contact page shows 5 scripts and 2 stylesheets, with TTFB near 340 ms on both. Similar TTFB and a large gap in file counts point at code added to the product template, not the server.
2. One slow first run
- Situation
- Illustrative example: a merchant tests a large collection page right after publishing new products and sees a bad TTFB, then wonders whether the theme is broken.
- Input
https://yourstore.com/collections/summer-dresses- Reading the result
- The first run might report a TTFB of 1,100 ms, while two repeat runs report 380 ms and 360 ms. The spread suggests cache state rather than a permanent problem. Judge the repeat values, and only worry if every run stays above 600 ms.
3. Checking an uninstall actually helped
- Situation
- Illustrative example: after removing a pop-up app, the owner wants proof that its code is gone and not just hidden.
- Input
https://yourstore.com/- Reading the result
- Before the removal the homepage might list 31 render-blocking files (scripts plus stylesheets); after turning off the App embed and deleting leftover snippet code it might list 19. The drop shows less code is delivered. It says nothing about rankings, so also confirm the title tag and H1 are still present.
Common mistakes
- Testing only the homepage. Product and collection templates load different apps than the homepage, so a clean homepage result can hide a heavy product page.
- Trusting a single run. One reading moves with cache state and network conditions, so repeat each URL before changing anything.
- Treating HTML size as full page weight. The test downloads only the HTML document, so large product images and script files are not in the Page size (HTML) figure.
- Uninstalling an app and stopping there. Leftover snippets in theme.liquid can keep loading code for an app that is gone, so search the theme files and re-run the test.
- Blaming a specific app from one number. The result shows counts, not owners, so switch off one App embed at a time and compare before and after.
Frequently asked questions
Why is my Shopify store slow after installing apps?
Many apps add their own JavaScript and CSS to the storefront, and those files load on pages whether or not the app is visible there. Run the Page Speed & Size Test on a product page and a plain page such as /pages/contact, then compare the counts of external scripts and stylesheets. A big gap suggests app or theme code on the product template. The test cannot tell you which app owns each file, so switch off one App embed at a time and re-run.
What is a good TTFB for a Shopify store?
The test rates under 200 ms as good, under 600 ms as a warning and anything slower as bad. Treat one reading as a hint, not a verdict, because the figure moves with cache state and with the distance between the SeoMods server and your store. Run the same URL three times, note the middle value, and compare product, collection and home pages separately. If only one template is slow, look at what that template loads before blaming anything else.
Can this tell me why my Shopify store is not showing on Google?
No. It checks how quickly a page responds and how heavy the HTML is, not whether Google has indexed the page. A store that is not showing on Google needs Search Console to check indexing status, plus a look at your sitemap and robots.txt.liquid. Speed is a separate question, and a fast result says nothing about whether a page is indexed or will rank. Use this test only for the speed side of the problem.
Does this show my full Shopify page weight including images?
No. The test downloads only the HTML document from a single server-side request, so Page size (HTML) is the weight of the markup, not of images, scripts or CSS files. It does count how many images, external scripts and stylesheets the HTML references, which is a useful proxy when you compare pages. For per-file weight you would need a browser-based tool, and the Image Alt Checker covers alt text on product images.
How often should I re-run the test on my Shopify store?
Run it before and after any change that touches the storefront: installing or removing an app, switching themes, editing theme.liquid, or adding a pop-up. Use the same three URLs each time, such as the homepage, one collection and one product, and keep the numbers in a note. Because a single run varies, repeat each one. This gives you a before-and-after trail, which is the most reliable way to see whether a specific app or theme edit added weight.
Reference: The Ahrefs guide to Shopify SEO notes that bulk title and meta description templates are not built into Shopify, which is one reason stores end up adding more apps.