Plugins like WP-Optimize, WP Rocket, and Website Speedy can inflate Lighthouse scores by deferring JavaScript. However, this does not enhance user speed and may even be detected by testing tools.

Hacking Lighthouse Scores

The Illusion of Speed: How to Hack Lighthouse Scores

We are phasing out FREE speed monitoring. Here’s a summary of the timeline, reasons, and recommended alternatives – PLUS monitoring and one-time INSIGHTS testing.

End of FREE Monitoring

Discontinuing FREE Monitoring: Switch to PLUS or INSIGHTS

Recordings from the UX Day talk on how web performance impacts trust and business, embedded presentation, checklist with tool links, and thanks to the organizers.

UX Day 2026

UX Day 2026: Materials from the Talk "Speed: The Invisible Part of Web UX"

Web speed is not a technical detail but a crucial business topic. At PageSpeed.ONE, we help dozens of websites each year achieve higher speeds and a more pleasant user experience.

Winners of the PageSpeed.ONE Awards 2025: jrc.cz and woox.sk

A fast website isn't just crucial for e-commerce. Political parties in this year's parliamentary elections have shown they understand this as well. According to PageSpeed.ONE measurements, major players such as SPOLU, ANO, Piráti, and STAN have fast and technically sound websites.

How Fast Are the Websites of Czech and Slovak Political Parties?

Martin Michálek discusses on the WebTop100 podcast why website speed remains crucial for business. He delves into why Core Web Vitals aren't enough, myths about hosting, common company mistakes, and how AI is changing the role of websites.

Martin Michálek on WebTop100 Podcast: Website Speed, Business, and the Future of Websites in the AI Era

A fast website means more customers and higher conversions. That's why we're expanding our traditional competition for the fastest online store and announcing the PageSpeed.ONE Awards 2025.

Introducing PageSpeed.ONE Awards 2025

News

Discover three new ways to prevent losing conversions due to a slow website. Over the years at PageSpeed.ONE, we've tackled website speed for numerous projects.

PageSpeed.ONE Expands Services to Include WordPress, Shoptet Optimization, and SpeedCare Monitoring

An interview that clarifies why speed isn't a relic of 2005, but a pivotal factor in your e-shop's success.

Martin Michálek on Ecommerce Bridge: Speed Isn’t Just a 2005 Topic – How Fast Are Local E-Shops, and How to Handle Hosting?

Martin Michálek discussed web speed in the Socials podcast, with a focus on its influence on marketing and business websites. He also delved into the numbers we've measured and provided specific tips on how to address speed.

Podcast Interview on Socials: How Web Speed Impacts Business

For the third time, I attended Europe’s most prestigious conference on "web speed".

Beyond Core Web Vitals: A Report from performance.now() 2024

The fastest e-shop of 2024 is iWant.cz, and we warmly congratulate its creators, as well as the teams behind Hornbach.cz and Altisport.cz, who made it to the podium. But what do the data say, and what can you take away beyond mere comparisons with the largest (and fastest) Czech e-shops? In this text, we focus on common mistakes e-shops repeatedly make, optimization recommendations that always work, and finally, we spotlight the winner of the poll.

The Fastest E-Shop of 2024: Common Mistakes, What Works, and What Defines the Winner?

Which e-shop operating in the Czech market is the fastest? Just like last year, we've focused on the top hundred Czech e-shops to rank them based on Google user data, announce the winner, and ponder what this means for the entire Czech e-commerce landscape.

The Fastest E-Shop of 2024: Who Won and How Did the Big Players Fare?

Just like last year, we focused on the top hundred Czech e-shops to compile a ranking based on Google user data, announce the winner, and reflect on what this means for the entire Czech e-commerce scene.

The Fastest Czech E-shop of 2024 is iWant.cz

The goal of PageSpeed.ONE is to accelerate websites for users. We strive to achieve this through speed consultancy and our monitoring tool. Naturally, we know we can't speed things up alone. That's why we established the WebPerf.cz community and have already organised two meetups this year, one in Prague and one in Bratislava.

WebPerf.cz Meetups

The mission of PageSpeed.ONE is to enhance awareness of the benefits of fast websites through lectures, meetups, and articles.

Introducing PageSpeed.ONE Help

At the start of the new school year, I attended a conference organized by Smashing Magazine in Freiburg

Report from SmashingConf Freiburg 2023 🥨

Recently, I gave a talk at the Plzeň meetup of our Frontendisti.cz community, presenting ten tips on the latest in web speed, tailored specifically for developers.

Faster Web Made Easy: New Technologies and Tools for Developers

Which Czech e-shop is the fastest? Can large e-shops be fast enough? And how do you measure it?

The Fastest Czech E-shop: Hornbach, 3v1, and T-shock

This year's WebExpo is behind us. It was delightful. It was intense.

WebExpo 2023: Talks on Speed Optimization

The year 2022 marked a dynamic beginning for PageSpeed.ONE. We ramped up our consultancy services focused on web speed optimisation and developed our own speed tester. We also expanded into a four-member team – alongside myself, Michal, and Zuzka, we welcomed Radek.

Our Achievements: Successful Speed Optimisations and New Clients in 2022

The methods for measuring and optimizing web page speed are constantly evolving. New web standards are being introduced, new tools developed, and new metrics proposed.

Web Speed: 12 Developments of 2022

Large conferences make a comeback post-Covid. At the end of October, the third Performance.now() event took place in Amsterdam, eagerly anticipated by us.

Full Throttle Return: Perf.now() Conference 2022

Discover how to effectively monitor your website's speed using our speed tester. It's easy and the tester is available for free.

Monitoring Website Speed with PageSpeed.ONE (Tutorial)

PageSpeed.ONE made its presence felt at this year's WebExpo, with our own Michal Matuška delivering a presentation in English on “Optimising Core Web Vitals With Web Fonts”.

PageSpeed.ONE's Presence at WebExpo 2022

On April 7th, I had the opportunity to talk about measurement at the SEO Restart conference. In the following text, I'll convey the main idea – to show the simplest way to obtain speed data and the recommended way to pass it on to developers.

Measuring Website Speed for Marketers Step-by-Step

Recently, I had the opportunity to speak at the first-ever Czech frontend conference. Given that web speed is a topic I deal with daily, the theme of the talk was clear.

Common Mistakes That Ruin Web Vitals

Everything you need to know for creating fast websites all in one place.

2021 Website Speed Checklist

How does he perceive the connections between SEO/marketing and website speed? That and much more in today's video.

Interview with Filip Podstavec from Marketing Miner

Speed is a living organism, so let's take a look at the next batch of updates.

Tips and News from the World of Speed vol. 2

In our new show "Speed Matters", we aim to bring interesting topics about web acceleration every month.

Tips and News from the World of Speed vol. 1

We have united under the PageSpeed.ONE brand, driven by our mission to enhance user experience through faster websites. Publishing articles aligns perfectly with our strategy, especially in times when meeting in person isn't as straightforward.

Getting Started with Our Blog: What to Expect Here?

Release 4.14 introduces Chrome UX Report histograms in the Domains report, a more sensitive Watchdog, the phase-out of FREE monitoring, and various website enhancements.

Monitoring v4.14

Version 4.14: Histogram in Domains and a More Sensitive Watchdog

Release 4.13 introduces a public API, new app navigation, SEO improvements, and a link to the schedule for ending FREE monitoring.

Monitoring v4.13

Version 4.13: Public API, App Navigation, and Changes to FREE Monitoring

Release 4.12 unveils a new marketing website with monitoring at its core, an AI Bot Strategy service, and the enhanced PageSpeed.ONE Insights speed test.

Monitoring v4.12

Version 4.12: New Website, AI Bot Strategies, and Enhanced Speed Test

Release 4.11 introduces PageSpeed.ONE Insights for quick web testing with business recommendations, the Core Web Vitals Live Chrome Extension, and a new visual identity for PageSpeed.ONE.

Monitoring v4.11

Version 4.11: Insights, Chrome Extension, and a New Brand

Release 4.10: measurement history, manual testing (beta), custom measurement times (beta), faster test starts, new guidance, and transition to the PageSpeed.ONE domain.

Monitoring v4.10

Version 4.10: PageSpeed.ONE Domain, History, Manual Testing, Custom Times…

Version 4.9.1 brings several enhancements and fixes to improve your experience with our website speed monitoring.

Monitoring v4.9.1

Monitoring v4.9.1: New Speed Score (SPS), Watchdog Changes

From version 4.9, we are adding an additional set of data to help you quickly identify issues and make better optimization decisions.

Monitoring v4.9

Monitoring 4.9: More Data from Chrome UX Report

Keep track of our app development in real time.

Changelog

The main changes? You can now automatically start a trial version of the PLUS tests, we’ve sped up and refined the initial web testing phase, and continue to teach the PageSpeed.ONE interface in English.

Monitoring v4.8

Monitoring v4.8: Automatic Trial and More

We have deployed version 4.7.2 of our PageSpeed.ONE monitoring system. This release brings a few adjustments to the user interface and technical background, enhancing your navigation within the application and increasing measurement reliability.

Monitoring v4.7.2

Monitoring v4.7.2: English Website Version and Minor Enhancements

We have implemented a measurement change that will affect server response values (TTFB metric) in synthetic data.

Monitoring v4.7.1

Update of TTFB Measurement in Synthetic Data (release 4.7.1)

We have a fresh update that has taught our monitoring to speak English and test more swiftly than before.

Monitoring v4.7

Monitoring 4.7: New Version, New Language. Hello, World!

The new version of Monitoring PLUS from PageSpeed.ONE introduces speed scores, significant improvements to working with notes, and more accurate Watchdog notifications. Discover how these changes can simplify your speed optimization and website performance monitoring.

Monitoring v4.6

Last week, changes in AWS infrastructure caused temporary instability in measurement results, including our Watchdog and its notifications.

Measurement Update (v 4.5.1)

Introducing the latest version of PageSpeed.ONE web speed monitoring. We have focused on better explaining the features of PLUS monitoring for those interested.

Monitoring v4.5

Monitoring PageSpeed.ONE Version 4.5: New Landing Pages, Help, Monthly Navigation Types

We’ve been working hard (really hard) on help documentation, as well as on the automatic launch of PLUS monitoring. However, the main new feature will delight anyone who loves truly fast pages.

Monitoring v4.4

PageSpeed.ONE Speed Monitoring Version 4.4 Released: Navigation Types, New Test Setup, and a Heap of Help

We have added help documentation for educational purposes, integrated Watchdogs into the Summary report, display specific Metric values, and have more interface improvements.

Monitoring v4.3

Speed Tester Version 4.3: Help, Watchdog Improvements, CrUX Graphs and Much More

We are delighted to announce the release of the latest version of pagespeed.one/app, our web speed monitoring tool.

Monitoring v4.2

Beyond the Speed Watchdog and notifications, PLUS monitoring offers numerous other innovations to simplify tracking and evaluating your website's speed.

Tester v4.0 - Technical

Further Innovations in PLUS Testing (Stable Infrastructure, "Technical" Report, and Graph Annotations)

In the third part of the series, we introduce its flagship or rather the standard-bearer as a key member of the news army. Let’s focus on the Speed Monitor.

Monitor and Notifications

Paid Tests PLUS: Speed Monitor and Notifications

We build Monitoring PLUS for anyone who professionally manages websites and knows that speed matters because it improves business metrics.

Tester PLUS

PLUS Tests for All Pros Seeking a Faster Web

Following the recent release of version 4.0, we have prepared another batch of enhancements for our web speed monitoring tool. Alongside a host of minor tweaks and bug fixes, we bring you several user-facing updates.

Tester v4.1

Tester Version 4.1: Charts in Reports, Clearer Modals, and More

We are delighted to introduce you to version 4.0 of our speed tester, a project we've been refining over the past few months.

Tester v4.0

Tester 4.0: New “Summary” Version, New Metrics, New Graphs (and Much More)

Our website speed testing tool has made another leap forward, and we are pleased to introduce the updates in version 3.1.

Tester v3.1

PageSpeed.ONE Speed Tester: Updates in Version 3.1

As some of you might have noticed, the PageSpeed.ONE website has got a new look, and we are gradually launching the third version of our web speed tester.

Tester v3.0

PageSpeed.ONE Tester: What's New in Version 3.0

Last year, when we at PageSpeed.ONE embarked on developing the tester, we had two objectives in mind: to create a tool that seamlessly integrates into our web speed measurement workflows and to raise awareness about the importance of speed itself.

Tester v2

Tester Version 2: User Data from the Chrome UX Report and Other Enhancements

Before diving into our tool, take a quick tour of the features it offers.

Welcome!

Welcome to PageSpeed.ONE’s Website Speed Tester!

Psychology, conversions, and Google. Why should you care about a fast website?

Why Web Speed?

Why Optimise Web Speed?

Occasional speed testing isn't enough. Without continuous speed monitoring, hidden issues remain undiscovered, historical data for analysis is absent, and trends that could cost your website conversions and visitors are easily overlooked.

Why Monitoring?

Monitoring Web Speed: Why It's Important and How to Use It Effectively

Core Web Vitals (CWV) is Google's foundational set of metrics designed to reflect website loading speed and user experience. Let’s discover the metrics it includes, why they matter, and how to measure them.

Core Web Vitals (CWV)

Core Web Vitals: Everything About Speed Metrics

The introductory page, known as the "Summary", provides a quick overview of the current state of web speed across various contexts and types of measurements

Report "Summary"

To optimize LCP, it is crucial to identify the "LCP element", which is the largest element in the viewport.

LCP Element

How to Identify the LCP Element

Let’s explore how to avoid CLS issues and how to fix them if they occur.

CLS Optimisation

Optimising CLS Metrics

Let us explore the challenges you might face with the Largest Contentful Paint (LCP) metric and how to optimise it effectively.

LCP Optimisation

Optimising the LCP Metric

The “Domains” report displays the speed status of measured domains. It is the most crucial report when it comes to the speed development of the entire website.

“Domains” Report

INP is not the easiest metric to optimise, so we have selected the most common issues and solutions from our experience.

INP Optimisation

INP Metric: 7 Tips for Optimisation

Every day, Watchdog monitors the speed of the measured pages of your website. If any key metric changes, the Speed Watchdog will alert you.

“Watchdog” Report

The Pages Report in PageSpeed.ONE monitoring shows the status and evolution of the speed for measured URLs.

Pages Report

TTFB indicates the speed of the server (or infrastructure), the server-side application, and also the network speed between the server and the user's browser.

Time To First Byte (TTFB)

Technical indicators of a website are often overlooked, yet they can play a crucial role in enhancing your site's speed and performance. Discover the importance of monitoring data volume, request count, and other technical metrics, and how they can impact user metrics such as LCP or FCP. Learn how to utilize our PageSpeed.ONE services for effective monitoring and optimization of your website's technical indicators.

“Technical” Report

Measurement History combines notes and synthetic measurements into a single view. Available only for PLUS tests. We describe the table, manual measurements (beta), and integration with test run details.

Report "History" (Log)

Measurement History (Log)

First Contentful Paint (FCP) is a metric that measures the time from when a page starts loading to when any part of the page's content is rendered on the screen.

First Contentful Paint (FCP)

In the test run detail, you can see the results of specific testing for one of your website’s URLs.

Test Run Detail Report

Proper settings are crucial for accurate speed measurement, so please pay close attention to this text.

Test Settings

This page allows you to edit personal user information and change the default language for monitoring.

User Settings

Back/forward cache (or BFcache) is a browser optimization that allows instant back and forward navigation. It significantly enhances the browsing experience, particularly for users with slower networks or devices.

BFcache

BFcache: Speed Up Users' Navigation in Browsing History

At PageSpeed.ONE, we often delve into very specific issues. Even so, I am still amazed at the level of detail we explore. The same goes for data compression, which we will examine in this article.

Gzip and Brotli Compression

Web Compression with Gzip and Brotli: Are You Doing It Right?

Understanding different navigation types is crucial, as some are markedly faster than others. From a web speed optimization perspective, the goal is to steer as many users as possible towards faster navigation types.

Navigation Types

Properly configured notifications and their evaluation are part of the "performance budgets" topic and the absolute foundation of caring for your website’s speed.

Watchdog: Alerts

Speed Watchdog Alerts

The world of the Largest Contentful Paint (LCP) metric is akin to the adrenaline-fuelled realm of motor racing – it's a relentless battle against time.

Rank	Website	Speed Coefficient
1	iwant.cz	7.07
2	hornbach.cz	7.91
3	altisport.cz	9.14
4	zalando.cz	9.17
5	lekarna.cz	9.17
6	onlineshop.cz	9.80
7	e-kondomy.cz	10.43
8	allegro.cz	10.57
9	kamody.cz	10.71
10	insportline.cz	10.75

The Fastest Czech E-shop of 2024 is iWant.cz

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The Fastest Czech E-shop of 2024 is iWant.cz

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