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

UX Day 2026

UX Day 2026: Presentation Materials “Speed: The Invisible Aspect of Web UX”

Web speed isn’t a technical detail but a vital business topic. Every year, PageSpeed.ONE helps numerous websites achieve faster speeds and a more pleasant user experience.

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

A fast website isn't just important for e-shops. Political parties in this year's parliamentary elections have shown they understand this too. According to PageSpeed.ONE measurements, major players like SPOLU, ANO, Pirates, and STAN have fast and technically sound websites.

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

Martin Michálek discusses why web speed remains crucial for businesses on the WebTop100 podcast. He addresses why Core Web Vitals aren't enough, debunks hosting myths, highlights common company mistakes, and explores how AI is changing the role of websites.

Martin Michálek on WebTop100 Podcast: Web 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 e-shop and announcing the PageSpeed.ONE Awards 2025.

Introducing PageSpeed.ONE Awards 2025

News

We're offering three new ways to ensure your conversions don't slip away due to a slow website. At PageSpeed.ONE, we've tackled web speed for dozens of projects over the years.

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

An interview explaining why speed isn't a relic from 2005 but a crucial factor in your e-commerce success.

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

Martin Michálek discussed website speed on the Socials podcast, emphasizing its impact on marketing and business websites. He also shared metrics we've measured and specific tips for improving speed.

Podcast Interview on Socials: How Website Speed Affects Business

For the third time, I ventured to visit the most prestigious conference on "web speed" held in Europe.

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

The fastest e-shop of 2024 is iWant.cz, and we heartily congratulate its creators, as well as the teams behind Hornbach.cz and Altisport.cz, who also made it to the podium. But what do the data reveal, and what can you learn from them, beyond comparisons with the largest (and fastest) Czech e-shops? In this text, we focus on common errors that e-shops repeatedly make, optimization recommendations that always work, and finally, we take a closer look at the contest winner.

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

Which e-shop operating in the Czech market is the fastest? 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 ponder the implications for the entire Czech e-commerce sector.

Fastest E-Shop of 2024: Who Won and How Did Major E-Shops Fare?

Just like last year, we focused on the top 100 largest Czech e-shops, using Google user data to rank, crown the winner, and ponder the implications for Czech e-commerce as a whole.

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

The mission of PageSpeed.ONE is to accelerate websites for users. We strive to achieve this through speed consulting and our monitoring tool. Naturally, we understand that we can't undertake this acceleration alone. That's why we've established the WebPerf.cz community and have already organized two meetups this year—one in Prague and another in Bratislava.

WebPerf.cz Meetups

The mission of PageSpeed.ONE is to raise awareness about 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, at the Pilsen meetup of our Frontendisti.cz community, I gave a talk with ten tips on the latest web speed innovations, 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 we measure this?

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

This year's WebExpo is over. It was beautiful. It was intense.

WebExpo 2023: Talks on Speed Optimization

The year 2022 marked a dynamic beginning for PageSpeed.ONE. We offered more web speed optimization consulting services than ever before and developed our proprietary speed tester. We also expanded to a four-member team, adding Radek alongside Michal, Zuzka, and myself.

Our Achievements: Successful Speed Optimizations and New Clients in 2022

The way we measure and optimize website speed is constantly evolving, with new web standards being introduced, new tools developed, and new metrics proposed.

Web Speed: 12 Innovations of 2022

After the COVID era, big conferences are making a comeback. The third edition of Performance.now() was held in Amsterdam at the end of October, and we were eagerly awaiting it.

Back in Full Swing: Perf.now() Conference 2022

Learn how to efficiently monitor the speed of your websites using our speed tester. It’s easy, and the tester is available for free.

Monitoring Website Speed with PageSpeed.ONE (Tutorial)

This year's WebExpo was graced by the presence of PageSpeed.ONE, with our Michal Matuška delivering a talk on “Optimising Core Web Vitals With Web Fonts” in English.

PageSpeed.ONE's Presence at WebExpo 2022

On April 7th, I had the opportunity to discuss web speed measurement at the SEO Restart conference. This text will share the core idea—showing the simplest way to gather speed data and how to relay it effectively to developers.

Step-by-Step Guide to Web Speed Measurement for Marketers

Recently, I had the opportunity to speak at the very first Czech frontend conference. As website speed is a topic I deal with daily, the subject of the talk was clear.

Common Mistakes That Ruin Web Vitals

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

Web Speed Checklist 2021

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

Interview with Filip Podstavec from Marketing Miner

Speed is like a living organism, so let's dive into another batch of updates.

Tips and News from the World of Speed vol. 2

In our new series “Speed Matters,” we aim to bring engaging topics about enhancing web performance every month.

Tips and News from the World of Speed vol. 1

We've come together under the PageSpeed.ONE brand to enhance user experience through faster websites. Publishing articles fits perfectly into our strategy, especially in times when meeting in person isn't so straightforward.

Starting a Blog: What Can You Look Forward To?

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

Monitoring v4.11

Version 4.11: Insights, Chrome Extension, and New Branding

Release 4.10: measurement history, manual testing (beta), custom testing times (beta), faster test initiation, new help 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 introduces several enhancements and fixes to improve your experience with our web speed monitoring.

Monitoring v4.9.1

Monitoring v4.9.1: New SPS Score, Watchdog Changes

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

Monitoring v4.9

Monitoring 4.9: More Data from the Chrome UX Report

Track the evolution of our application in real time.

Changelog

The main changes? You can now automatically start a trial of PLUS tests, we’ve sped up and refined the initial phase of web testing, and we 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. This release brings several adjustments to the user interface and technical backend, enhancing your navigation within the application and improving measurement reliability.

Monitoring v4.7.2

Monitoring v4.7.2: English Version and Minor Enhancements

We have implemented a change in measurement 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’re excited to introduce our latest update, which teaches our monitoring tool to speak English and test faster than ever before.

Monitoring v4.7

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

The new version of Monitoring PLUS by PageSpeed.ONE introduces speed scores, significant improvements in note-taking, and more accurate Watchdog notifications. Discover how these changes can streamline your speed optimization and performance tracking.

Monitoring v4.6

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

Measurement Update (v 4.5.1)

Introducing the next version of the PageSpeed.ONE web speed monitoring. We focused on better explanations of the PLUS monitoring features 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 the help section. Plus, we've automated the launch of monitoring PLUS. The main update, however, will delight anyone who loves truly fast pages.

Monitoring v4.4

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

We have added help documentation, enhancing our audience’s education, integrated Guardian into the Summary report, displayed specific Metric values, and made further interface improvements.

Monitoring v4.3

Speed Tester Version 4.3: Help Documentation, Guardian Enhancements, CrUX Graphs, and More

We are delighted to announce the launch of the latest version of app.pagespeed.cz, our web speed monitoring tool.

Monitoring v4.2

Beyond the Speed Watchdog and notifications, the PLUS tester introduces a host of new features that simplify monitoring and evaluating your website’s speed.

Tester v4.0 - Technical

Additional Updates in PLUS Testing (Stable Infrastructure, “Technical” Report, and Notes in Graphs)

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

Monitor and Notifications

Paid Tests PLUS: Speed Monitor and Notifications

PageSpeed.ONE PLUS tester is designed for anyone professionally managing websites who understands that speed matters because it enhances business metrics.

PLUS Tester

PLUS Tests for All Pros Who Want a Faster Web

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

Tester v4.1

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

We are thrilled to introduce you to version 4.0 of our speed tester, on which we have been working for the past few months.

Tester v4.0

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

Our web speed tester has taken another leap forward, and we’re delighted to introduce the features in version 3.1.

Tester v3.1

PageSpeed.ONE Speed Tester: What’s New in Version 3.1

As some of you may have noticed, the PageSpeed.ONE website has donned a new look, and alongside, 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

When we at PageSpeed.ONE began developing our tester last year, we had two goals. To create a tool that seamlessly integrates into our web speed measurement workflows, and to use it as a means to enhance awareness of speed itself.

Tester v2

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

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 Page Speed?

Why Optimise Website Speed?

Occasional speed checks aren’t enough. Without continuous speed monitoring, hidden issues remain unseen, you lack historical data for analysis, and trends that can cost your site conversions and visitors are easily overlooked.

Why Monitor?

Web Speed Monitoring: Why It’s Crucial and How to Use It Effectively

Core Web Vitals (CWV) is a fundamental set of metrics from Google designed to capture website loading speed and user experience. Let’s explore what metrics it includes, why they matter, and how to measure them.

Core Web Vitals (CWV)

Core Web Vitals

The introductory page, known as "Summary", serves as a quick display of the current state of your website’s 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 within the visible part of the browser.

LCP Element

How to Find the LCP Element?

Let’s explore together how to avoid CLS issues and how you can fix them when they occur.

CLS Optimization

CLS Metric Optimization

Join us as we explore common issues with the Largest Contentful Paint (LCP) metric and how to optimize it most effectively.

LCP Optimization

Optimizing the LCP Metric

The “Domains” report showcases the speed status of measured domains. It is the most critical report concerning the overall speed development of the website.

“Domains” Report

INP isn’t the easiest metric to optimize, so we’ve selected the most common issues and solutions from our experience.

INP Optimization

INP Metric: 7 Tips for Optimization

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 reveals the status and evolution of the speed of measured URLs.

“Pages” Report

TTFB reflects 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 pivotal role in enhancing your site’s speed and performance. In this article, discover why it’s crucial to monitor data volume, request count, and other technical metrics, and how they can impact user metrics like LCP or FCP. Learn how to leverage our PageSpeed.ONE services for efficient monitoring and optimization of your site’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 connection with the test run detail.

“History” Report (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.

First Contentful Paint (FCP)

The test run detail provides results of a specific test of 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 your personal information and change the default language in monitoring.

User Settings

The back/forward cache (or BFcache) is a browser optimization enabling instant back-and-forth navigation, significantly enhancing the browsing experience, especially for users on slower networks or devices.

BFcache

BFcache: Accelerate User Navigation Through Browsing History

At PageSpeed.ONE, we often delve into very specific issues. Yet, I’m still amazed at the depths we reach. It was the same with data compression, which we’ll explore in this article.

Gzip and Brotli Compression

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

Understanding the different types of navigation is crucial because some are significantly faster than others. From a web speed optimization perspective, the goal is to direct as many users as possible to the 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 thrill of a high-speed racetrack—it’s an endless race against time.

Largest Contentful Paint (LCP)

Largest Contentful Paint (LCP) Metric: A Guide to Faster Web Loading

Google introduces the new Interaction to Next Paint (INP) metric, set to replace the First Input Delay (FID) metric among the top three Core Web Vitals metrics in March 2024.

Interaction to Next Paint (INP)

Interaction to Next Paint (INP): Tackling Slow Interactions

Annoyed when an ad pushes away the text you’re reading? Frustrated when content jumps just as you’re about to click, causing a misclick?

Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) Metric: How to Identify and Eliminate Unwanted Page Shifts

The Speculation Rules API offers us the ability to preload or even pre-render another page. This can lead to nearly instantaneous page loading for users transitioning between pages, enhancing their overall web experience.

Speculation Rules

Speculation Rules API: The Path to Instant Page Loading

Watchdog monitors the speed of your monitored website pages daily through Monitoring PLUS. If a key metric changes, Speed Watchdog alerts you. This text explains who should evaluate these reports and how.

Watchdog: Evaluation

How to Evaluate Watchdog Reports?

Cloudflare acts as an intermediary between your website and its visitors. Unlike a regular CDN (Content Delivery Network), it’s more than just a system for distributing images and files.

Monitoring v4.9.1: New SPS Score, Watchdog Changes

What's New in Version 4.9.1?#

Preferences

What's New in Version 4.9.1?