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...

👴 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!

The DebugBear request waterfall back when it was still built on top of Highcharts 😂

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-...

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...

Recorded a video explaining how to use WebPageTest and interpret the request waterfall! www.youtube.com/watch?v=vdpq...

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...

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 🕒 Wed Nov 19 at 6 PM CET / 5 PM GMT / 12 PM ET / 9 AM PT (🧵 2/2)

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-...

Made some design tweaks to our HTML size analyzer tool! www.debugbear.com/html-size-an...

Responsive images are a web performance best practice... but embedding all versions as Base64 in the HTML isn't 🙃 Test your own website here: www.debugbear.com/test/website...

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...

⏳ 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...

Great post from the folks @debugbear.com on the new DevTools MCP server and how you can use it for performance debugging:

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-...

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...

British trains when they’re late: sowry, here’s your money back 🥺 Deutsche Bahn: sends international letter, “not our fault, 25% refund denied” 😤

Want to debug websites in Safari on Mac or iOS? You need the Safari Web Inspector! 🐛 Debug CPU and memory 🚶 Step through JavaScript code 📚 View log output 📱 Inspect websites on your phone www.debugbear.com/blog/safari-...

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...

I thought the browser console was simple... I was wrong 🤯 It's actually packed with hidden features: 🖼️ Logging images ✨ AI explanations 🥹 Logging tables 🔧 Console utilities ($0, $_, ...) 🔎 Advanced filters 🔥 Live expressions New article below! www.debugbear.com/blog/chrome-...

🤔 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-...

Wrote up an article over at @debugbear.com, just published today! It's a pretty light (yet still dense 😅) 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-...

CSS Weekly #605 🚀 Optimizing The Critical Rendering Path 😶‍🌫️ Focus by Negation Effect 🔎 Dynamic Focus Zoom Effect 🌄 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

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

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...

Learned about the Ripple Delete feature in ScreenFlow today. Makes life so much easier. New video: www.youtube.com/watch?v=gnol...

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.

We just published a new free tool: test your website's Time to First Byte metric across 10 global test locations! 🚀 Check server response time 💻 View CDN cache status 🌎 See what region the response was served from

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.

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?

Love people at #perfnow sharing performance tools they wish existed. Great ideas for free @debugbear.com tools we could build!

Been taking a look at the new annotations features in the Chrome DevTools performance tab www.debugbear.com/blog/chrome-...