What is a third-party script, and how does it slow a store?
Definition
A third-party script is a piece of code your page loads from another company's server: analytics, ads, chat, reviews, popups, A/B testing. Each is useful and each costs download time and processing on the shopper's device.
How they slow a store
Every script is another request, and many load more scripts of their own. They compete with your own code for the browser's attention, which delays taps and can push the layout around as they inject content.
How to keep them in check
List every third-party host your pages call, write down what each does, remove those no longer used, and delay those not needed for the first view. Apps you uninstalled may have left their code behind in the theme.
What the audit shows
It groups requests by host and totals their weight, and names the owner where it recognises the file, such as a theme asset, a WordPress plugin or a known Shopify app.
Frequently asked questions
Are all third-party scripts bad?
No. Payments and analytics are needed. The point is to know what you load and why.
How do I find what is slowing me down?
The network tab in browser developer tools sorted by size and domain is the quickest view.