How to spot and remove old app code slowing down your Shopify store
Shopify store speed matters. Slow sites frustrate customers, lower conversion rates, and can even affect search rankings. Yet many store owners don’t realize their site is being dragged down by something simple: leftover code from apps that were uninstalled long ago.
When an app is removed, it doesn’t always clean up after itself. The result is that unnecessary JavaScript files keep loading in the background, adding weight to every page load. Let’s go through how to check for this problem and what you can do to fix it.
Why old app scripts keep slowing you down
When you install a Shopify app, it often adds JavaScript files to your theme. These files let the app display widgets, track actions, or run certain features.
The problem is that when you uninstall the app, the code isn’t always removed. This means:
Your site keeps calling a file that no longer serves any purpose.
Visitors’ browsers have to fetch it, slowing things down.
Over time, you could have multiple “ghost” files still being loaded.
For stores that test new apps frequently, the effect can snowball. Even a few extra requests can impact load times, especially on mobile.
Step 1: Check your uninstalled apps
Shopify makes it simple to see what’s no longer active in your store. Go to:
Settings → Apps and sales channels → Uninstalled
This list will show you all the apps you’ve removed. Keep it open while you check for leftover files.
Step 2: Run a site test with Yellow Lab Tools
You don’t need to be technical to find extra JavaScript files. A free tool called Yellow Lab Tools can do the heavy lifting.
Here’s how:
Visit yellowlab.tools and run a test on your homepage and a product page.
Scroll down to the “Requests number” section.
Click it to expand, scroll down to JS files, then review the list of files.
Look for file URLs that end in .js but don’t include “shopify” in the domain. Those are third-party scripts.
Step 3: Match files to old apps
Not sure what a script belongs to? Here’s a quick way to confirm:
Open the uninstalled app’s page in the Shopify App Store.
Launch the demo store, then copy the URL of a page where the app would be loading.
Run the same Yellow Lab test on that demo store.
Compare the script URLs to the ones from your own site.
If they match, you’ve found the culprit.
If you’re stuck, you can also paste part of the script URL into Google. Most times you’ll find the developer or product it’s linked to.
Step 4: Get old dode removed safely
Finding leftover files is one thing, but removing them needs caution. Deleting theme code directly can cause problems if you’re not confident with Liquid or JavaScript.
Here’s the safer route:
Download a copy of your theme first. Always keep a backup before changing code.
Contact the app developer. Ask if their app leaves code behind and request removal instructions.
Hire help if needed. If you don’t have in-house support, a Shopify developer can clean things up quickly.
FAQ
Do all uninstalled apps leave behind code? Not all. Some remove themselves cleanly, but many don’t. It depends on how the developer built the app.
Will deleting leftover scripts improve site speed? Yes, in most cases. Fewer files mean faster loading times, especially on mobile connections.
What if I can’t tell which app the code came from? You can Google the domain inside the URL or ask in a Shopify community forum.
Can I remove scripts myself? If you’re comfortable editing theme files, you can. But it’s best to have a backup and know what you’re doing.
How often should I check for leftover code? Every few months, or anytime you uninstall apps regularly. It’s a quick check that can save headaches later.
Wrapping up
Old app scripts might not sound like a big deal, but they add unnecessary weight to your Shopify store. Over time, they create slower load times and a less smooth customer experience.
By checking your uninstalled apps, running a quick test, and asking developers for support, you’ll keep your store lean and running fast.
