"Slow" is harder to diagnose than "down," because the cause can live in four different places: Shopify's platform, your theme and apps, third-party scripts, or the internet infrastructure between your store and your customers. Here is how to tell which one you are dealing with, fastest checks first.
Is it Shopify, or is it just you?
Check Shopify's live status and test your store from a second network (phone on cellular). Shopify's platform ran the 180 days ending July 2026 with zero major incidents, so persistent slowness is usually not the platform, but brief degradations do happen and mostly resolve without action (the June 2026 events are documented in how often does Shopify go down).
Is it an infrastructure incident upstream of everyone?
When Cloudflare has a bad day, a large slice of the internet gets slow at once, including apps and scripts your store loads. Cloudflare logged 2 major incidents totaling 910 minutes in the 180-day window, making it the least reliable infrastructure provider StatusBird tracks (comparison here). If your store, your apps, and half the sites you visit are all sluggish simultaneously, stop debugging your theme.
Is it app and script weight?
The most common cause of chronic (rather than sudden) slowness: accumulated apps injecting scripts. Each review widget, popup, heatmap, and pixel adds load time, and uninstalled apps sometimes leave code behind. Audit with Shopify's built-in speed report, then remove or defer what you do not actively use. Sudden slowness after installing an app points at that app.
Is one third-party script blocking your page?
A slow or failing external script (a font CDN, a chat widget, an analytics tag) can hold up rendering for every visitor while its host struggles. This is the sneaky overlap between "slow" and "someone else's outage": your store is technically up while a dependency's bad day makes it unusable. This is exactly why monitoring your stack, not just your storefront, matters.
Is it actually slow for customers, or just for you?
Your own browser's cache, extensions, or network can lie to you. Test in incognito, from another device, and ideally with a synthetic check from another region before acting on "it feels slow."
The monitoring angle
Speed problems caused by third-party degradation announce themselves in status changes before they show up in your analytics. StatusBird watches Shopify, Cloudflare, and 80+ services your store loads from, and its own-store monitoring checks your actual storefront's response from the outside, so "slow for everyone" pages you instead of waiting for conversion reports to sag.
Start monitoring your stack free with StatusBird: 3 services, no credit card required. Pro is $29/month for all 84 services with SMS, email, Slack, Teams, and Discord alerts within 2 minutes of a status change.