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How NitroPack Helps with Total Blocking Time and First Input Delay
How NitroPack Helps with Total Blocking Time and First Input Delay
Updated this week

Total Blocking Time (TBT) is not an actual performance metric, but by improving it, we can boost First Input Delay – the actual Core Web Vital metric.

With NitroPack, optimizations are automatically applied to help you achieve better speed and real-world performance.

How NitroPack can improve TBT (and FID) to boost performance

The execution of JavaScript is the most important factor that affects this metric. So delaying and deferring as much JavaScript as possible will have the biggest impact here.

When you analyze your site using PageSpeed Insights or Lighthouse, in the test results, find the Diagnostics section, and click on the Avoid long main-thread tasks tab.

This will give you a list of the longest tasks on the main thread to focus on.

You can use the following NitroPack features to reduce the impact:

➡️ Reduce the impact of JavaScript code

By delaying JavaScript execution

When JavaScript is delayed until user interaction, it will improve FID/TBT. This feature is available for use in our Ludicrous Mode.

➡️ Minimize main thread work

By using our “Combine CSS into one resource” and “Reduce Unused CSS” features

These options will minimize main thread work and automatically compress it with GZIP, helping transfer smaller file sizes.

➡️ Reduce JavaScript execution time

By using our “Combine JS into one resource” feature along with our automatic GZIP compression

Combining JS into one resource and our automatic compression with GZIP allows you to speed up JavaScript execution time.

➡️ Keep request counts low and transfer sizes small

By using our “Enable Font Compression Upgrade” feature

When this option is enabled, NitroPack will optimize fonts by upgrading their compression to WOFF2 format. This can reduce the size of these fonts by up to 50%.

By using our “Font Subsetting (Remove Unused Glyphs)” feature

This will remove the Unused Glyphs from the fonts used, minimizing the requests and also file sizes.

Additional information about the feature can be found in our article:

📌 If you need any assistance or have questions, reach out to our support team at [email protected] or via this link:

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