Core Web Vitals Monitor

This tool is designed to monitor Core Web Vitals of a URL in real-time. Using data from the Google PageSpeed Insights API (Lighthouse), it tracks key metrics: Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS).

Features

• Real-time monitoring of Core Web Vitals such as LCP, FID, and CLS for a website.
• Alerts when the LCP, FID, or CLS values exceed thresholds that may negatively impact user experience.
• Displays data in a table format for better readability using the tabulate library.
• Automatic cleaning of values by removing units like "s" from LCP and FID to allow proper processing.

Requirements

• Python 2.7
• Python libraries:
  • requests - to make HTTP requests to the Google PageSpeed Insights API.
  • tabulate - to display results in a table format.
  • colorama - to colorize the terminal output.

Installation

1. Install dependencies: Before using this tool, make sure to install the required libraries. Run the following command in your terminal:

   pip install requests tabulate colorama

2. Running the Tool: Once dependencies are installed, you can run the tool with the following command:

   python core_web_vitals_monitor.py

   The tool will prompt you to enter the URL you want to monitor.

Usage

1. Enter URL: After running the tool, you will be prompted to enter the URL of the website you want to monitor.
2. Real-Time Monitoring: The tool will monitor Core Web Vitals every 60 seconds and display metrics like LCP, FID, and CLS in a clear table format.
3. Alerts: If any metric exceeds the set threshold (LCP > 2.5 seconds, FID > 100ms, CLS > 0.1), the tool will display an alert in the terminal.

Example Output:

Core Web Vitals Monitor

Monitoring Core Web Vitals for: https://example.com

Fetching Core Web Vitals data...

╒══════════╤═════════╕
│  Metric  │  Value  │
╞══════════╪═════════╡
│   FID    │  1.5 s  │
├──────────┼─────────┤
│   LCP    │  1.4 s  │
├──────────┼─────────┤
│   CLS    │  0.003  │
╘══════════╧═════════╛

Waiting for the next check...

If LCP, FID, or CLS exceed the threshold, you will see alerts like:

Alert: LCP is too high! (Consider optimizing loading time)
Alert: FID is too high! (Consider reducing input delay)
Alert: CLS is too high! (Consider reducing layout shifts)

Threshold Customization

• LCP: If greater than 2.5 seconds, considered too slow.
• FID: If greater than 100ms, considered too high.
• CLS: If greater than 0.1, considered too high.

You can customize these threshold values in the code inside the monitor_vitals() function if necessary.