It is not the hosting
Shopify runs on infrastructure most businesses could not afford to replicate. If your store is slow, the cause is on your side: what you uploaded and what you installed.
That is good news, because it means the problem is within your control rather than requiring a platform migration.
Images first, as always
Product photography uploaded straight from a camera or supplied by a manufacturer is frequently several megabytes per image. A collection page showing twenty products can therefore carry tens of megabytes.
- Resize before uploading — 2000px wide is ample for almost any use
- Compress to around 80% quality, which is visually indistinguishable
- Let Shopify serve responsive sizes rather than one large file everywhere
- Lazy-load anything below the fold, particularly on collection pages
Then the apps
We routinely find app scripts accounting for more than half a store's page weight. The single most effective speed work on most stores is an app audit.
Look at what each app injects and where. An app that only affects the product page should not be loading on the homepage, and many do.
Theme code and leftovers
Themes accumulate modifications, and uninstalled apps leave snippets behind. Over three years a theme can carry a substantial amount of code serving no current purpose.
A theme audit — identifying what is still used and removing what is not — is unglamorous work that frequently produces a noticeable improvement.
Measure properly
| Test | Why |
|---|---|
| Mobile, on mobile data | How most customers actually experience it |
| Homepage, collection and product | Different pages have different problems |
| Before and after each change | So you know what worked |
| Real user data over time | Laboratory tests miss real conditions |
Testing your homepage on office fibre and concluding the store is fast is the most common measurement mistake.