@mattzeunert.com
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๐ฅ 164
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Working on web performance optimization, founder of
@debugbear.com
HTML parsing speed depends a lot on how powerful the device that's visiting the website is. When I measure parse time on my laptop it takes under 7 milliseconds to process one megabyte of HTML. But on a low-end Android phone it takes 88 milliseconds!
www.debugbear.com/blog/html-pa...
about 5 hours ago
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๐ด Back in my day when you told the computer to do something it just did it. No code formatters or pre-commit hooks putting you on hold for 10 seconds!
2 days ago
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The DebugBear request waterfall back when it was still built on top of Highcharts ๐
3 days ago
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Recently a customer was telling me no analytics data was reported for one of their websites. I used the script below to find the culprit: a script in Google Tag Manager that assigned a different navigation value! Learn about other JavaScript debugging techniques:
www.debugbear.com/blog/chrome-...
3 days ago
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Our JSON Size Analyzer now can now identify images embedded in your JSON code! Spotted an example yesterday where 42 images were part of the JavaScript hydration state. Test your JSON here:
www.debugbear.com/json-size-an...
Or check HTML and embedded scripts:
www.debugbear.com/html-size-an...
4 days ago
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Recorded a video explaining how to use WebPageTest and interpret the request waterfall!
www.youtube.com/watch?v=vdpq...
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How to analyze website performance with WebPageTest
Learn how to check your website speed with the free WebPageTest tool https://www.catchpoint.com/webpagetest Or try the DebugBear speed test as an alternativeโฆ
https://www.youtube.com/watch?v=vdpqOXEfqyc
5 days ago
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What's a good strategy to speed up your website? And how should you respond to different types of regression alerts? My new article explains the role of monitoring and different types of performance data for website optimization.
www.smashingmagazine.com/2025/11/effe...
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Effectively Monitoring Web Performance โ Smashing Magazine
There are lots of tips for [improving your website performance](https://www.debugbear.com/blog/improve-website-performance?utm_campaign=sm-10). But even if you follow all of the advice, are you ableโฆ
https://www.smashingmagazine.com/2025/11/effectively-monitoring-web-performance/
6 days ago
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reposted by
Estela Franco
7 days ago
Then,
@mattzeunert.com
will walk us through Synthetic Web Performance testing with
@debugbear.com
. All details and add-to-calendar (with zoom link) at
performanceobserver.dev
๐ Wed Nov 19 at 6 PM CET / 5 PM GMT / 12 PM ET / 9 AM PT (๐งต 2/2)
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PerformanceObserver: A virtual web perf meetup
Join the PerformanceObserver virtual performance meetup to get all the latest web performance news and hang out with the community.
https://performanceobserver.dev/
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Just published an article on JavaScript debugging! We'll cover the basics of pausing execution and inspecting state, as well as looking at some advanced breakpoint conditions.
www.debugbear.com/blog/chrome-...
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How To Debug JavaScript In Chrome DevTools | DebugBear
Learn how to set pause execution, inspect application state, and discover advanced breakpoint functionality.
https://www.debugbear.com/blog/chrome-javascript-debugger
7 days ago
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Made some design tweaks to our HTML size analyzer tool!
www.debugbear.com/html-size-an...
7 days ago
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Responsive images are a web performance best practice... but embedding all versions as Base64 in the HTML isn't ๐ Test your own website here:
www.debugbear.com/test/website...
9 days ago
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The biggest factor slowing down the BitBucket homepage: massive CSS selectors! Test your own CSS files here with our free tool:
www.debugbear.com/css-size-ana...
10 days ago
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โณ Why would Chrome decide against loading an image even though it can see it in the HTML? Most browsers have a concept of "tight mode" where the number of non-critical requests is limited in order to give priority to render-blocking resources. More:
www.smashingmagazine.com/2025/01/tigh...
28 days ago
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reposted by
Barry Pollard
about 1 month ago
Great post from the folks
@debugbear.com
on the new DevTools MCP server and how you can use it for performance debugging:
add a skeleton here at some point
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I played around with the Chrome DevTools MCP server over the weekend. The performance recommendations it gives are the same as in Lighthouse/DevTools, but having the integration with the AI model is helpful.
www.debugbear.com/blog/chrome-...
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Performance Debugging With The Chrome DevTools MCP Server | DebugBear
Learn how to use the Chrome DevTools MCP server with AI models to analyze web performance and get concrete optimization recommendations.
https://www.debugbear.com/blog/chrome-devtools-mcp-performance-debugging
about 1 month ago
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What UK shop has the fastest self-checkout machine? Last Sunday I went on a tour around town to find out!
www.debugbear.com/blog/self-ch...
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What's The Fastest Self-Checkout: An Input Latency Analysis | DebugBear
We put 8 self-checkout machines in different UK stores to the test: how quickly do they respond to user input, what does the user see, and are there annoying extra steps before checkout?
https://www.debugbear.com/blog/self-checkout-input-latency
about 2 months ago
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British trains when theyโre late: sowry, hereโs your money back ๐ฅบ Deutsche Bahn: sends international letter, โnot our fault, 25% refund deniedโ ๐ค
about 2 months ago
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reposted by
DebugBear
3 months ago
Want to debug websites in Safari on Mac or iOS? You need the Safari Web Inspector! ๐ Debug CPU and memory ๐ถ Step through JavaScript code ๐ View log output ๐ฑ Inspect websites on your phone
www.debugbear.com/blog/safari-...
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How To Use The Safari Developer Tools | DebugBear
Learn how to use Safari's developer tools to debug your website on Mac OS and iOS.
https://www.debugbear.com/blog/safari-developer-tools
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reposted by
DebugBear
4 months ago
Sometimes servers don't send HTTP response data in the right order. Our new article explains why request priority matters for HTTP/2 and HTTP/3 connections, and how poor server-side support can impact page speed.
www.debugbear.com/blog/http-pr...
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Many Servers Don't Properly Support HTTP Prioritization | DebugBear
Loading the most important resources first is key to improving website performance. However, even when resources are correctly prioritized, servers don't always adhere to the request prioritiesโฆ
https://www.debugbear.com/blog/http-prioritization
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I thought the browser console was simple... I was wrong ๐คฏ It's actually packed with hidden features: ๐ผ๏ธ Logging images โจ AI explanations ๐ฅน Logging tables ๐ง Console utilities ($0, $_, ...) ๐ Advanced filters ๐ฅ Live expressions New article below!
www.debugbear.com/blog/chrome-...
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How To Use The Browser Console: An In-Depth Guide | DebugBear
The Console tab in Chrome DevTools is extremely feature-packed! Learn how to get started and explore its more advanced features.
https://www.debugbear.com/blog/chrome-browser-console
5 months ago
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๐ค Page speed optimizations in Google search results mean that some page content can be loaded without ever connecting to the website server! Just published this article explaining how it's possible to view content even for a website blocked in /etc/hosts!
www.debugbear.com/blog/google-...
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Why can I still load a website that's blocked on my computer? | DebugBear
How Google performance optimizations make it possible to access websites without connecting to the website server.
https://www.debugbear.com/blog/google-blocked-website
6 months ago
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reposted by
Cory Miller
8 months ago
Wrote up an article over at
@debugbear.com
, just published today! It's a pretty light (yet still dense ๐ ) introduction to optimizing performance with Next.js and keeping an eye out for some of the "gotchas" of using the framework.
www.debugbear.com/blog/nextjs-...
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A Guide to Performance Optimization with Next.js | DebugBear
Find out why performance matters for your website, what common Next.js performance issues are, and what you can do to fix them.
https://www.debugbear.com/blog/nextjs-performance
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reposted by
CSS Weekly
9 months ago
CSS Weekly #605 ๐ Optimizing The Critical Rendering Path ๐ถโ๐ซ๏ธ Focus by Negation Effect ๐ Dynamic Focus Zoom Effect ๐ Favicon & Gif in 2025 Featuring
@mattzeunert.com
,
@kevinpowell.co
,
@en.sitnik.ru
,
@ryantrimble.com
,
@geoffreygraham.bsky.social
,
@tahazsh.bsky.social
,
@jhey.dev
.
cssw.io/issue-605
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CSS Weekly Issue #605
Find out how to optimize the Critical Rendering Path, how to create cool-looking CSS effects, how to work with favicons and animated images in 2025, and more.
https://cssw.io/issue-605
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Made a video investigating a truly niche LCP regression! Learn about how LCP is defined, discover bizarre edge cases in contentfulness, and see how to check for changes in metric definitions.
youtu.be/aX7VRto8gVE
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Is this the world's WEIRDEST Largest Contentful Paint element?
YouTube video by DebugBear
https://youtu.be/aX7VRto8gVE
10 months ago
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When talking to customers about their page speed metrics, one of the most common issues is that their PageSpeed Insights scores don't match what they see in DebugBear. Here's a new video with a detailed explanation!
www.youtube.com/watch?v=t_UG...
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PageSpeed Insights vs. Lighthouse: understanding the Performance score
YouTube video by DebugBear
https://www.youtube.com/watch?v=t_UG-1ks-jU
10 months ago
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Learned about the Ripple Delete feature in ScreenFlow today. Makes life so much easier. New video:
www.youtube.com/watch?v=gnol...
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Web Performance Audit: Early Hints, Hydration State, and a Lazy Loaded LCP Image
YouTube video by DebugBear
https://www.youtube.com/watch?v=gnol1gWfKaA
10 months ago
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reposted by
DebugBear
10 months ago
Not sure how to fix Cumulative Layout Shift issues on your website? This guide shows three concrete examples of how to identify the cause of CLS and apply a solution.
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Avoid Large Layout Shifts: 3 Practical Examples | DebugBear
Want to fix CLS issues on your website? Here's a step by step guide of how to debug three common causes of large layout shifts on your website.
https://www.debugbear.com/blog/avoid-large-layout-shifts
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reposted by
DebugBear
10 months ago
We just published a new free tool: test your website's Time to First Byte metric across 10 global test locations! ๐ Check server response time ๐ป View CDN cache status ๐ See what region the response was served from
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TTFB Test: Check Time to First Byte On Your Website
Measure Time to First Byte performance from multiple global test locations.
https://www.debugbear.com/test/ttfb
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I was talking to a user yesterday who thought web performance was impacting his SEO. But it turned out that the performance of his website was fine. Why was he concerned anyway? PageSpeed Insights gave him a poor Performance score in the diagnostic section.
10 months ago
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I'd love to have some kind of senior ops unicorn working at DebugBear. Someone who can handle B2B sales convos, knows a bit about page speed, can write onboarding emails, create a home working policy, do some customer success... Anyone have advice on how to find that person?
11 months ago
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Love people at
#perfnow
sharing performance tools they wish existed. Great ideas for free
@debugbear.com
tools we could build!
about 1 year ago
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Been taking a look at the new annotations features in the Chrome DevTools performance tab
www.debugbear.com/blog/chrome-...
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How To Annotate A Chrome DevTools Performance Trace | DebugBear
Learn how to add annotations to Chrome DevTools performance recordings to document your findings and discuss them with your team.
https://www.debugbear.com/blog/chrome-devtools-performance-annotations
about 1 year ago
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