Pay Attention ❤: Max Potential First Input Delay (Max Potential FID) is no longer used as a metric in Google, as it has been deprecated.
When users interact with your website, they expect immediate responses. However, if your page is still loading or processing tasks, there might be a delay before it responds to their actions. This delay is measured by a metric called Max Potential First Input Delay (Max Potential FID). Max Potential FID captures the longest possible delay a user might experience before the page becomes responsive, making it an important metric for user experience. In this article, we’ll explain what Max Potential FID is, why it matters, and how to optimize it for a more interactive website.
Max Potential First Input Delay (Max Potential FID) measures the longest delay a user might experience when they try to interact with a webpage. Specifically, it calculates the maximum amount of time between a user's input (like a click or tap) and when the browser can actually begin processing that interaction.
Max Potential FID is particularly relevant for heavy pages with large JavaScript files, where users might try to interact before the page is fully loaded. The goal is to keep this delay short, ensuring a smoother experience.
- Good: Less than 130 milliseconds (ms) – This is ideal, offering a near-instant response to user interactions.
- Needs Improvement: Between 130 ms and 250 ms – This is acceptable but could be optimized for a faster response.
- Poor: More than 250 ms – This is slow, and users are likely to experience noticeable delays, which can lead to frustration.
A low Max Potential FID score means the page can handle user inputs quickly, creating a responsive and engaging experience.
- Improved User Experience:
A low Max Potential FID score ensures that users don’t experience noticeable delays when they try to interact with the page. Immediate responsiveness keeps users engaged and satisfied.
- Reduced Bounce Rates:
If users experience a long delay when they try to interact with a page, they may leave out of frustration. By minimizing Max Potential FID, you reduce the likelihood of users abandoning your site.
- Better Core Web Vitals Score:
Google includes Max Potential FID as part of its performance metrics in Core Web Vitals. Sites with good Max Potential FID scores are more likely to rank higher, improving visibility and traffic.
- Large JavaScript Files: Heavy JavaScript files that take time to process can delay the browser’s ability to respond to user inputs.
- Long Tasks on the Main Thread: Tasks that take more than 50 milliseconds to execute on the main thread block other tasks, including user interactions, increasing Max Potential FID.
- Render-Blocking Resources: CSS or JavaScript files that need to load before the page can become interactive can hold up other actions, creating a delay for users.
- Optimize JavaScript Execution: Minimize and compress JavaScript files to reduce their size, enabling faster execution. Break down large scripts and load only what’s necessary on each page.
- Defer or Async Non-Essential JavaScript: Use the async or defer attributes for JavaScript files that aren’t essential for initial interactivity. This allows the browser to prioritize important tasks first.
- Reduce Main Thread Blocking Tasks: Break down long tasks into smaller ones, so the main thread isn’t occupied for long periods. This makes it easier for the browser to respond to user interactions quickly.
- Use Code Splitting: Code splitting helps load only the necessary parts of JavaScript based on user interaction. By loading components on-demand, you reduce the burden on the main thread.
- Use Web Workers: Web Workers can handle complex tasks in the background, away from the main thread, freeing up resources for user interactions.
- Optimize Third-Party Scripts: Limit third-party scripts, like ads or analytics, as they can block the main thread and increase Max Potential FID. Only include essential third-party scripts, and load them asynchronously if possible.
While Max Potential FID focuses on the potential delay in responding to user interactions, it’s helpful to consider it alongside metrics like First Input Delay (FID) and Total Blocking Time (TBT). These metrics provide a more complete view of page responsiveness and interactivity, helping you optimize for a better user experience.
Max Potential First Input Delay (Max Potential FID) is a critical metric for understanding and improving how quickly a page responds to user interactions. By optimizing JavaScript execution, breaking down long tasks, and deferring non-essential scripts, you can reduce Max Potential FID and provide a faster, more interactive experience for users. A low Max Potential FID score not only keeps users engaged but also improves SEO, making your site more competitive in search results. Prioritizing this metric as part of your performance optimization strategy will make your website feel responsive, reliable, and user-friendly.