No more heroes anymore?
Hi, I noticed the custom hero dialog has disappeared from the custom tab in the UI. I can't get custom heroes in the API anymore. I couldn't find anything in the documentation or in the release notes...
View ArticleHow looks server cache in WPT?
Could somebody show or explain me, how looks in WPT a waterfall of page, which loads from server cache?
View ArticlePrerendering vs. optimization?
Do i have a bug in my way of thinking? Or is this approach correct and efficient? There are many adjusting screws one can turn to optimize loading time. Some of them are easy, other not so easy, i.e....
View ArticleHow to optimize image progressive
I have website https://meovathay.vn/ and have issue about "Use Progressive JPEGs", result test: https://www.webpagetest.org/performance_...ess_images I don't really know how to "Use Progressive JPEGs"...
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Enabling Webpagetest in restricted staging environments.
Hey guys, I would love to be able to run WebPageTest on some of my staging environments but unfortunately, the staging environments are IP restricted . Is there a way to find a list of IPs WebPageTest...
View Article3rd party JS execution is slowing down the performance
Hi, Adobe launch scripts, i.e. scripts from asset.adobe.com is slowing down the site significantly. When we block this particular script the page loads very fast and when we do not block it, it takes...
View ArticleWhat means TTFB for files, which are loaded through keep-alive-ed connection?
What means TTFB for the firstly loaded file is clear. But if i look at further loaded files i see in their details TTFB too, and it is ways higher then zero. How can it happen, if all files are loaded...
View ArticleNEL reporting
I was trying to collect NEL (https://www.w3.org/TR/network-error-logging/) but I don't see them being generated. Normally Chrome would install a NEL policy upon receiving an HTTP header that instructs...
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Moto G4 - a terrible Mobile device goal for 2021?
Please correct me if I'm wrong, but I think that optimizing for the Moto G4 is no longer a good idea. ...and optimizing for it will drive us a little nuts because the lab tests are pretty erratic....
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How to find and evaluate "best case" TTFB?
What is the proper way to determine “best case” Time-To-First-Byte? (TTFB) And is this site's time good, average, or poor? Please share your knowledge and experience. I'll give some examples from my...
View ArticleIf inlining critical CSS, also load the file in the body?
I am looking into inlining our critical CSS to reduce our LCP time. Our site is responsive using Bootstrap, so we use different portions of our single CSS file for Desktop visitors than we do for...
View ArticleDocument Complete vs Load Event Start
Hello, Im running bulk tests and from the result file "aggregate.csv" i have the metrics Document Complete Load Event Start They have exactly the same values, which makes also sense when reading the...
View ArticleNavigation Timing API
Hello, WPT measures several technical metrics. Some of them are directly calculated with the Navigation Timing API (exposed via performance.timing) I want to understand how WPT metrics are calculated...
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How to tell if shared hosting is REALLY hurting page speed???
. I have read in many places that upgrading a site's webhosting plan will improve it's page speed. But in reality, will it really matter? My tiny experiment below says “no”. Please share your knowledge...
View Articlepage speed issue
Hi trying to figure out why my page load time is so slow and what can I do about it. Is it a server issue or bad coding. https://www.webpagetest.org/result/21030...ba71acab1/ Any help or opinion will...
View Article3g-end of life: what does it mean for webpagetest, Lighthouse and Core Web...
In 2021 3g will be shut down in Germany. However, the main testing environment of Lighthouse is 3Gfast, and for compatibility purposes we run WPT tests in 3Gfast too. What means 3g shutdown for us in...
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WebPageTest doesn't recognize Fastly CDN
Hello! Im using Cloudinary service(https://cloudinary.com/) to serve images for my website. Cloudinary uses Fastly CDN under the hood. When im trying to test my website using WebPageTest, results say...
View ArticleReasoning for using median for load time?
Hey, I would like to understand what the thought process was around choosing Load time as a basis for median calculation as opposed to TTI/LCP or any other metrics that are available? I ask this...
View ArticleUncaught ReferenceError: wptRequestData is not defined
Hi, Holding wpt private instance hosted on AWS. Suddenly facing below issues. Any suggestions? 1. Request details dialog/window/popup not displayed. getting below error Uncaught ReferenceError:...
View ArticleCLS issue only in field data - how to diagnose it?
The website of PageSpeed Insight is the only place, where i get CLS issue in both of field and lab data. Any other Lighthouse (by WPT, as API or by DevTools) displays CLS issue only in field data, not...
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