Category: Performance Testing Basics

Total Blocking Time

Total blocking time defines as the sum of all the long tasks (=Long Task processing Time – 50ms) between First Contentful Paint and Time To Interactive period which blocks the main thread and prevents the user from interacting with the web page. What is Long Task? In the UI Performance Testing term, the main thread…
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Time to Interactive

‘Time to Interactive’ is a very common but non-standardized UI metric that represents the time when a website is ready for user interaction. Here, ‘user interaction’ means when a user can provide an input in form of a click, select an option, insert a text etc. To make the definition more simply, let’s try to…
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Speed Index

Speed Index (SI) is a UI Performance Testing metric that calculates how quickly the content of the webpage is visually displayed to the end-users. Actually, the speed index is not a time-based unit. It is a score that represents the content loading speed of a web page. The lesser is the value of SI, the…
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Largest Contentful Paint

Largest Contentful Paint or LCP is one of the important metrics in UI Performance Testing. It provides the time when the largest element of the web page is loaded in the browser and ready to consume by the user. Also note that the LCP only counts the loading time of what is relevant to the user…
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First Meaningful Paint

First Meaningful Paint or FMP measures the visible time of the primary content of a website. It is the time when the bigger content of the website is visible to the end-user and gives a major layout changes impression to him. First Meaningful Paint also includes the loading of actual fonts. As per the definition…
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First Contentful Paint

First Contentful Paint or FCP is one of the important metrics in UI Performance Testing. It provides the time when the browser renders the first bit of content like text, image, non-white canvas etc. It gives the first impression to the user that the page is actually loading. Behind the concept of FCP, there is another…
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