Speeding up Shoptet: what was really slowing a large shop
The short answer: a Shoptet store usually gets slow because of what was added to it over time, meaning add-ons, custom scripts and heavy images. On Malvarosa, a shop with almost four thousand products, the menu downloaded 12.9 MB of images nobody saw on every page view. It did not need a new shop to fix that.
- 30 Oct 2026
- Patrik Zukal
Measure first, then fix
Malvarosa sells furniture and home decor in Czech and Slovak. The brief was to stop the pages jumping and make the site faster, on the live shop with no staging copy. The brief ruled out rebuilding the theme without proof that it would solve anything.
So every change was measured first, went live with a backup and a rollback path, and was checked on 10 to 15 page types in both languages. The numbers below are lab measurements. Google's field data covers 28 days, so I do not quote it as a result here.
12.9 MB of menu images nobody sees
The biggest brake was not where I expected it. Theme code rewrote the address of all 77 images in the dropdown menu from thumbnail to original. Instead of a 3.5 kB file, the browser fetched an original averaging 174 kB, shown only 140 px wide anyway.
Together that came to 12.9 MB on every page view, whether anyone opened the menu or not. Lighthouse reported just 3.8 MB because it did not manage to download the rest. If you only look at the score, you do not see the size of the problem. After the fix, originals load only when a submenu opens.
Pages jumping: a section exactly 192 px tall
Google measures page jumps as CLS and treats up to 0.1 as good. Malvarosa had 0.16 in Google's data. I found the cause on the category listing: in the second second of loading, a section 192 px tall was added to the page and everything below it jumped by exactly that much. The fix is simple once you know where: reserve the space in advance.
- Category listing on mobile: from 0.224 to 0.02.
- The same category in the Slovak version: from 0.224 to 0.008.
- Page jumps on desktop: from 0.163 to zero.
The homepage and the product page had no such problem (0.0004 and 0). Changing the theme across the board would have risked breaking pages that worked.
An add-on that did nothing and cost 431 kB
Every page downloaded a 431 kB search add-on, and search through it did not work. It is gone. Web fonts also blocked rendering, so the browser waited for them before drawing the page. Now it does not.
How to check your own shop
- In PageSpeed Insights, measure a category listing, not only the homepage. That is where Malvarosa's page jumps were.
- Keep field data and lab data apart. The first changes slowly, the second shows a fix straight away.
- Open your browser's developer tools, go to the Network tab, load the page and sort files by size. The largest ones often lead to something not even visible on the page.
- Go through your add-ons. One you no longer use may still load its code on every page.
- After every change, test the cart and checkout too, not only what you changed.
What speed work will not do
Part of the code belongs to Shoptet and you cannot reach it, so nobody can honestly promise a perfect score. And speed alone does not bring customers. That is why I do not quote a revenue uplift here: several things affect orders at once and a single number would be a lie.
Shoptet speed questions
- Do I need to replace my Shoptet theme to make it faster?
- Usually not. On Malvarosa, targeted fixes to code, images and add-ons did the job, along with reserving space for sections that load late. Replace the theme only when measurement shows it is the actual brake.
- How much does speeding up Shoptet cost?
- It depends on what the measurement finds. I go through the shop first at no charge, and you get the findings and one price for the fixes that follow from them.
- Why does PageSpeed show a different score every time?
- Lab measurement varies with server load and the test environment. One run says little. Measure several runs in a row and compare specific numbers, not the overall score.
Want to know what is slowing your shop?
Send me your shop's address. I measure it and you get specific findings with numbers, not a general list of tips.
Tell me what you need solved.
Whether you have a site that misbehaves or are only planning a new one, a few sentences are enough. You need neither a brief nor a budget yet, that is my job.
- Within three working days you hear from me, not from an assistant or an autoresponder.
- For an existing site you get a free, non-binding review with findings.
- For a new project a few questions about the scope, then the scope and one figure.
Prefer email or a call?patrik@patrikz.dev+420 774 318 382