Poor FID score? Here is how to improve the First Input Delay!

First Input Delay (FID) directly concerns the website development niche, so only an expert can brush up on the delay. Here we will elaborate on the ways the Web Development Company uses to improve the First Input Delay.

In the previous post, we spotlight the necessary information about the First Input Delay. So let us recall it briefly.

FID is a real-time user-centric web page performance metric to check the page's time to respond to the first user interaction. When a user taps a button/link, typically, the browser takes action and responds.

So simply, First Input Delay measures the delay between the first interaction (user input) and the page response to that interaction.

What is a Poor FID score?

FID measures the delay time only and not the processing time; its unit is milliseconds. So a good FID score means the time is less than 100 ms.

However, delay time being above 300 ms is a poor score indicating to improve the First Input Delay. Thus, the time between 100 to 300 ms is average. So you can imagine that how much unpleasant user experience will the score above 300 ms will have on the users. More specifically, prompting to leave the website/ web page.

What is the need for optimizing the FID? 

Evidently, the first impression matters the most. So how the first time a user interacts with your webpage is the user experience. And it will be how the users will perceive your web performance. However, increased first input delay will undoubtedly impart a negative impression.

Besides, Google Page Experience Update has made the core web vitals an SEO ranking factor, and FID is the third core web vital. So there is a great need for improving the first input delay.

Now you know the importance of optimizing, let's jump on:

How to improve the First Input Delay? 

Common causes of the poor FID score include heavy JavaScript, monopoly of the long-running task in JavaScript, and unused JavaScript. Because the browser gets busy dealing with them and there comes a delay in responding.

Optimizing the 3rd Party Scripts 

Web page(s) has plenty of third-party scripts to make it more interactive. For instance, they can be the ads, analytics, widgets like Social media buttons (Facebook, Twitter), Video player embeds (YouTube).

However, if they are not optimized, they significantly increase the loading time. So the first tip is to optimize all the third-party scripts. More specifically, lazy loading – on-demand loading (when needed) can also solve your problems.

Speed up the JavaScript Code 

Usually, the long-running tasks in JavaScript take over the main thread and block the User Interface (UI), making the page unresponsive. Therefore, what you can do is to split the long-running tasks into small tasks. It will take out the stress from the main thread by providing intervals between the tasks and freeing up the browser for request processing.

Reduce the Load from the Main Thread 

In addition to the above, the Web Development Company frees up the main thread as possible. To do so, it runs the long tasks on the background threads instead of the main thread.

Optimizing the CSS Code

Alongside the above, optimizing the CSS also improves the FID as it saves space, increases compatibility, and increases speed. This process includes minimizing, compressing, and removing the markup and CSS files. That is getting rid of the unused CSS.

Remove Unused JavaScript & Polyfills

As we mention above, unused JavaScript puts the load on the browsers. The same is the case with the Polyfill (a code needed for browsers that do not support a specific feature/ website). Therefore, it is best to put them off at a future time or eliminate them. As for JavaScript, you can check it by a checker tool like the Chrome DevTools, configure, and leave only the code necessary for work.


Caching is the best way to boost the user experience of the page. It let you store the previously browsed and downloaded content and files. So whenever the user(s) revisit the website, and browser does not have to load and relaunch the content. Thus, saving a lot of time, minimizing the server load, and improving the page performance – leading to good FID.

Image Optimization

Lastly, the company optimizes the images present on the page. As a result, it lets you have enough time, capacity, etc., for request and code transferring and processing.

All tips and techniques favorably improve the First Input Delay. Thus, sign up with a top-tier Web Development Company knowing insights to overhaul the FID at best. Then, be quick about it and get your website user experience back on track and enjoy high SEO rankings.

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