Mantys Core
Founder of MantysLAB

Maxime

Maxime founded MantysLAB and builds Mantys Core, a cloud-powered performance plugin for WordPress.

Through Mantys Media, his freelance activity, he works hands-on on client WordPress sites: page builders such as Divi and Elementor, WooCommerce stores, tracking and consent setups.

The guides on this site come from that work: problems met on real sites, measured in the browser, and the fixes that held.

Areas of expertise

  • Core Web Vitals
  • WordPress
  • Critical CSS
  • JavaScript
  • Cache
  • WebP
  • Divi
  • Elementor
  • WooCommerce

Guides by Maxime

Core Web Vitals · 11 min

How to speed up a WordPress site: where to start, and in what order

Speeding up WordPress is not a list of thirty tips to switch on at once, it is a diagnosis: read your visitors’ data, find which metric fails on which template, fix the cause in the right order (server, images, CSS, JavaScript), and change one thing at a time.

JavaScript · 9 min

Delay JavaScript execution broke my site: how to find the script at fault

Delaying JavaScript breaks a site in five mechanical ways (a missing dependency, a page event that already fired, a first click swallowed, a chain stuck on one script, a visitor never counted), and each one leaves a signature you can read in the browser, so you can exclude one script instead of switching the whole option off.

Core Web Vitals · 8 min

How to fix layout shift (CLS) on Divi and Elementor

On page builders, most layout shift comes from six sources (images without dimensions, styles that arrive after the first paint, web fonts swapping, headers and banners added by scripts, sliders before they start, embeds), and each one is fixed by reserving the space before the content arrives.

Images · 7 min

My hero is a background image: why it slows LCP and how to fix it (Divi, Elementor)

A CSS background image is invisible to the browser until the stylesheet is downloaded and applied, it has no srcset, and builders often lazy load it with JavaScript, so the hero starts late; the best fix is a real image, and the next best is a preload per device and no lazy loading on that section.

Images · 7 min

The LCP image is not the same on mobile and desktop: how to preload the right one

When the largest image differs between phone and desktop, a single preload makes one of them download an image it will not show, or download the hero twice, and the fix is one preload per device, with the same srcset and sizes as the image, placed right after the viewport tag.

Core Web Vitals · 8 min

PageSpeed and Search Console disagree: how to read lab and field data

PageSpeed’s score is one simulated visit on a deliberately slow phone and network, while Search Console reports what your real visitors lived through over 28 days, so the two can disagree in both directions: a green lab with a poor field when your audience is slower than the test, and a mediocre lab with a green field when it is faster.

CSS · 8 min

Remove unused CSS broke my layout: how to find the missing styles

A used-CSS pass keeps only the rules it saw in use on one snapshot of the page, so anything that was not on screen at that moment (an open state, the other device, content loaded later, an icon font, an entrance animation) loses its styles, and each of these gaps has a signature that tells you which rule to put back.

JavaScript · 8 min

How to make Axeptio load faster (without breaking consent)

An Axeptio banner rarely arrives late because of Axeptio itself, it arrives late because its chain of requests (settings, SDK, project configuration, font) queues behind everything else the page loads, so the fixes are to lighten the competition, never delay the consent tool, load it early, drop the font you do not use, and customize it without fighting its markup.

Caching · 11 min

How to speed up a WooCommerce store without breaking the cart

A WooCommerce store is two sites in one, a catalog that can be cached and optimized hard, and a transaction (cart, checkout, account) that must never be cached or trimmed, so a fast store starts by drawing that line, then fixes the cache, cart fragments, product images and scripts on each side of it.

Images · 8 min

Inline SVG: perfect for an icon, poison for an illustration

An SVG is not one single kind of image. A small icon inline is ideal, a heavy illustration inline bloats your page, and a raster photo hidden inside an SVG is the worst of all three. Here is how to tell them apart and pick the right format every time.

JavaScript · 8 min

How to choose a theme, and spot the ones that ship one giant JavaScript file

Before your first line of content, your theme decides what a browser must download, parse and run. The single choice that weighs most is how it ships its JavaScript: one splittable set of small files, or one giant block that pins the whole page to its slowest part.

CSS · 6 min

Why does my WooCommerce mini cart stop showing when I turn on Remove Unused CSS?

Your mini cart panel is hidden until someone hovers it, so a used-CSS pass removes its styles and a JavaScript delay stops it from opening. It comes back once you keep its styles in a safelist and let its scripts, cart fragments included, run.

Core Web Vitals · 9 min

How to speed up a Divi site and improve its Core Web Vitals (step by step)

A Divi site can be fast if you optimize in the right order, images first, then CSS, then JavaScript, and start with the levers that cannot break anything before touching the ones that can.

JavaScript · 5 min

Why does my burger menu only open on the second click?

If you turned on a JavaScript delay (loading scripts on the first click or after a timer), the very first tap on the burger wakes up the script loading, it does not open the menu. The menu only responds to the second tap. The fix: isolate the menu script and its dependencies out of the delay, or better, give it a vanilla menu with no dependency.

Core Web Vitals · 6 min

Which optimizations can you turn on without any risk of breaking your site?

There is a whole family of optimizations that cannot break your site, because they reduce file weight or give the browser hints, without ever changing what runs. Start with those: they win you the essentials, with your eyes closed.

CSS · 6 min

Why did my critical CSS break my menu / overlay (it shows up open on load)?

Critical-CSS generators only keep the styles for what is visible at the top of the page on load. Your elements that are hidden by default and opened on click (mobile menu, search overlay, modal, drawer) are judged useless and removed. The result: on load, they show up open, broken, unstyled.

Images · 5 min

Why does PageSpeed Insights still say “Properly size images” when I have a srcset?

Srcset offers the browser a list of sizes, but it is the sizes attribute that tells it which one to pick. If sizes is missing, wrong, or ignored, the browser downloads the largest image in the list, and PageSpeed flags it, srcset or not.

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