OpenCart Module

Core Web Vitals PageSpeed for OpenCart

Real speed for real shoppers. Measure LCP, INP and CLS where Google measures them, fix what slows your store down, and check every change before your customers see it.

Last Update: 28 Oct 2026

Version: 2.0.0

Compatibility: OpenCart 3.0.3.0 or newer and OpenCart 4.0.2.0 or newer (tested up to 3.0.5.1 and 4.1.0.4), PHP 7.2 or newer (OpenCart 4: PHP 8.0 or newer), MySQL or MariaDB

Download for OpenCart 3 Download for OpenCart 4 Get Pro Get a quote for a full fix

Why Core Web Vitals matter

Google ranks pages by the Core Web Vitals of real Chrome users: how fast the main content appears (LCP), how quickly the page reacts to clicks and taps (INP) and how stable the layout is (CLS). A good PageSpeed score in a lab test does not help if real shoppers still wait. This module works with the numbers that count: the speed of your real visitors.

What it does

Measures real visitors. LCP, INP, CLS, FCP and server response time of real page loads, mobile and desktop, the last 28 days. You see the slowest pages and the exact element that is slow.
Applies safe improvements. Loads the main image first, lazy-loads images and frames below the first screen, loads YouTube and Vimeo players on click, reserves space for images, shows text while fonts load, connects early to font and script servers, defers scripts, minifies HTML and adds browser caching rules.
Tests with Google. Runs PageSpeed Insights from your administrator area and compares the draft with the published settings, so you see the effect before you publish.
Checks your server and shop. PHP version, OPcache, page cache, server response of real visitors, the OpenCart cache, image formats and the number of installed modules.

Safe by design

Every change is a draft first. You check it in a preview on your own store and with PageSpeed Insights; your customers still get the published settings.
Publish when you are sure. Every published version is kept, and any of them is one click away. One button turns every optimization off.
Switches that can affect scripts or the layout are marked "Check preview".
The module never changes what Google sees compared to what people see: crawlers and shoppers get the same page.
Cart, checkout and account pages keep their scripts as they are. Works together with SiteGuarding SpeedUp.

Private by design

Speed numbers stay on your own store. No cookies, no IP addresses, no personal data, nothing is sent to other servers. The page address is kept without its query string, for up to 28 days.

Screenshots

Overview: Core Web Vitals of real visitors and the next steps

Real visitors: LCP, INP and CLS on mobile and desktop, the slowest pages and the elements to blame

Optimize: safe switches, a draft you check in the preview, then publish; every version can be restored

PageSpeed: Google tests of the draft and the published settings, with what to fix

Diagnostics: server and shop checks that affect speed

Settings: real visitor measurements, the PageSpeed key and who gets the optimizations

Pro, Pages: real visitor speed by page type and by page, 7 days to 12 months, CSV export

Pro, Monitoring: weekly PageSpeed tests of your key pages, reports and alerts by email

Pro, Advanced: critical CSS, preloads and priorities per page type, scripts and styles per page

Free and Pro

	Free Core Web Vitals PageSpeed	Pro Core Web Vitals PageSpeed Pro
Real visitor measurements	Whole store, 28 days	Per page and page type, 12 months, CSV export
What to blame (LCP, CLS, INP elements)	Top 5 for the store	For every page and page type
PageSpeed Insights tests	Manual, last 20 tests	Plus weekly monitoring of 10 pages, email reports and alerts
Safe optimizations, preview and rollback	YES	YES
Delay third-party scripts until the first interaction	-	YES
Host Google Fonts locally	-	YES
Engineer tools: critical CSS per page type, scripts per page, HTML rules	-	YES

Pro is an add-on to the free module. Plans for 1, 5 and 25 sites.

After the purchase, download the Pro add-on for your OpenCart version in your SiteGuarding account, install it next to the free module and enter your licence key on its Pro screen.

Get Pro

Need it done for you?

Some problems need a developer: a heavy theme, a slow module, a server that answers late. Our engineers review your store, fix the slow parts by hand and check the result on real visitor data. Order a performance audit or get a quote for a full fix.

Get a quote for a full fix

FAQ

Does it replace a cache?

No. It works together with page caches. For a fast server response use a page cache, for example SiteGuarding SpeedUp.

Will it break my store?

Every change is a draft until you publish it, and you can check it in a preview first. Rollback is one click. Cart, checkout and account pages keep their scripts as they are.

Do I need a Google API key?

Only to run PageSpeed Insights tests from the administrator area. The key is free. Real visitor measurements and all optimizations work without it.

What data does it collect?

Speed numbers of page loads, the page address without its query string, the page type and whether the screen is mobile or desktop. No cookies, no IP addresses, no personal data.

Which OpenCart versions are supported?

OpenCart 3.0.3.0 or newer and OpenCart 4.0.2.0 or newer. Each has its own file: download the one for your version.

Which database does it need?

MySQL or MariaDB, as OpenCart uses.

Requirements

OpenCart 3.0.3.0 or newer (tested up to 3.0.5.1) with PHP 7.2 or newer; OpenCart 4.0.2.0 or newer (tested up to 4.1.0.4) with PHP 8.0 or newer. MySQL or MariaDB.

Download

Free, no account needed. Keep the file name: OpenCart 4 takes the module code from it.

Download for OpenCart 3 Download for OpenCart 4

Installation

OpenCart 3.0.x

1. In the administrator area, open Extensions > Installer and upload opencart3cwv.ocmod.zip.

2. Open Extensions > Extensions, choose Modules, find Core Web Vitals PageSpeed and click Install, then Edit.

3. Real visitor measurements start at once. To speed up the store, put the recommended safe set in a draft, check it in the preview and publish.

OpenCart 4.0.2 to 4.1

1. Open Extensions > Installer, upload siteguardingcwv.ocmod.zip (keep the file name) and click Install.

2. Open Extensions > Extensions, choose Modules, find Core Web Vitals PageSpeed and click Install, then Edit.

3. Real visitor measurements start at once. To speed up the store, put the recommended safe set in a draft, check it in the preview and publish.

Pro: install the Pro add-on the same way (it works together with the free module) and enter your licence key on the Pro screen.

Updates

OpenCart has no automatic updates for modules: the module shows a notice on its Overview screen when a new version is out, with a download link.

OpenCart 3: upload the new file in Extensions > Installer, then open the module page once.

OpenCart 4: in Extensions > Extensions > Modules uninstall Core Web Vitals PageSpeed, in Extensions > Installer uninstall and delete it, then upload the new file, install it and install the module again.

Settings and measurements stay in both cases. Pro shows a new version on its Pro screen with a download button and the same steps. Pro updates come with an active licence.

Changelog

2.0.0
New module: real visitor Core Web Vitals, safe optimizations with draft, preview and rollback, PageSpeed Insights tests and speed diagnostics.