CSSPro – Eliminate Render-Blocking CSS for Lightning-Fast PrestaShop

Solve Render-Blocking for Faster Above-the-Fold Loads

CSSPro for PrestaShop uses today’s best practices—no magic tricks or voodoo—to solve one of the hardest challenges in eCommerce: eliminating CSS blocking to improve above-the-fold page rendering and real visitor experience.

CSS Pro User Guide

Front Office Demo (view source to see Preload in header)

The Problem

• PrestaShop themes and modules use the default PrestaShop attribute “none” for stylesheets, causing each CSS file to block browser rendering.
• This delays content visibility and increases bounce rates.
• Tools like Chrome DevTools and WebPageTest.org highlight these issues—especially slow First Contentful Paint and Largest Contentful Paint.

The Solution: Smart Preloads, Stylesheet Management & Stealth Testing

CSSPro targets these issues with two core features, plus safe testing:

1. Asset Discovery Dashboard:
   You can initiate CSS discovery simply by visiting the front office. CSSPro records every CSS file registered as your PrestaShop page is being prepared for render and displays them in a simple dashboard—where you can also manage how each stylesheet is loaded.
2. Critical CSS Preloads:
   By default, CSSPro injects preload tags for all CSS files directly into your site’s header. While advanced configuration options are available, this automatic preloading alone solves the core render-blocking problem and accelerates above-the-fold rendering.
3. A/B Testing and Stealth Mode:
   When you install and configure CSSPro, it enters stealth mode by default. Only your IP address (or additional IPs you specify) will see CSS discovery and loading changes, allowing for private review and A/B testing before launch. Add team or group IPs for broader testing. When you’re satisfied with the improvements, simply disable stealth mode to go live for all visitors.

Results You Can Measure

After setup, use Chrome DevTools or WebPageTest.org to confirm improvements in:

• First Contentful Paint (FCP)
• Largest Contentful Paint (LCP)
• Speed Index

Why It Matters

• Faster above-the-fold content: Visitors see key content almost instantly, reducing wait time and frustration.
• Better first impressions: Quick rendering makes your store feel modern and professional.
• Higher engagement and sales: Shoppers are more likely to stay and complete purchases when pages load smoothly.

Troubleshooting Tips

Some themes, including PrestaShop’s Hummingbird, use a stylesheet called theme.css that cannot always be safely preloaded. If you notice an issue where CSS appears briefly and then disappears (such as page styles flashing and then vanishing), set the Resource Hints option for theme.css to “none” in your CSSPro dashboard. This ensures compatibility and keeps your page styling consistent.

Trusted by PrestaShop Experts

We understand that many PrestaShop admins are cautious about installing new modules—often because of past issues with compatibility or performance. CSSPro is a mature solution, proven on multiple production shops without issue. Our motto is simple: We test so you don’t have to.

We’ve been developing robust PrestaShop solutions since 2009, focusing on stability, compatibility, and real results. You can count on:

• Battle-tested code: Deployed on high-traffic, real-world shops
• Excellent support: Fast responses from experienced developers
• Free installation & configuration: We’ll set up the module for you, following best practices
• Ongoing updates: Continuous improvements based on feedback and evolving standards

Choose CSSPro for peace of mind—so you can focus on growing your shop, not troubleshooting your modules.