Inline styles and CSS have been compared in terms of performance, with interesting results. In a recent experiment, a website was migrated from CSS to inline styles, and the performance differences were analyzed.
The experiment revealed that inline styles can be faster than CSS. When using inline styles, the website experienced improved load performance, resulting in smaller HTML and JS files. Additionally, browser render time, web vitals, and first contentful paint were all better with inline styles.
However, it should be noted that the performance differences may vary depending on the website. The experiment did not show any significant difference in server render time, HTML size, and JavaScript bundle size between inline styles and CSS.
Overall, the results suggest that inline styles may be a better option for performance, especially when it comes to browser render time and web vitals, particularly on mobile devices.

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Using inline styles can improve performance, resulting in smaller HTML and JS files, better browser render time, web vitals, and first contentful paint. Inline styles may be a better option for performance, especially on mobile devices.

The Performance Impact of Inline Styles vs CSS

Do you have your data available? What about sample files to actually see what was done, scale, etc? Would love to see some more depth to this to understand context.

I guess the tests have been conducted on initial load, for subsequent loads, performance would be better with cached external CSS file.

Can you provide the source or reference of this comparison as I am more interested in learning in depth about it!

are you kidding ? I really don’t think a complete website can be created only inline style. if you need responsive breakpoint what will you do ?

Who provided this data, what is it based on? Is there really any concrete data? Writing inline CSS just for the mobile view is absurd.