@vercel/speed-insights

What is @vercel/speed-insights?

@vercel/speed-insights is an npm package designed to provide insights into the performance of web applications. It leverages Google's Lighthouse to analyze and generate reports on various performance metrics, helping developers optimize their applications for better speed and user experience.

What are @vercel/speed-insights's main functionalities?

Generate Performance Report

This feature allows you to generate a performance report for a given URL. The `getSpeedInsights` function fetches the performance metrics and returns a detailed report.

const { getSpeedInsights } = require('@vercel/speed-insights');

async function generateReport(url) {
  const report = await getSpeedInsights({ url });
  console.log(report);
}

generateReport('https://example.com');

Custom Configuration

This feature allows you to customize the performance report by specifying options such as the strategy (mobile or desktop) and the categories of metrics to include in the report.

const { getSpeedInsights } = require('@vercel/speed-insights');

async function generateCustomReport(url) {
  const options = {
    strategy: 'mobile',
    categories: ['performance', 'accessibility']
  };
  const report = await getSpeedInsights({ url, options });
  console.log(report);
}

generateCustomReport('https://example.com');

Save Report to File

This feature allows you to save the generated performance report to a file. The `fs` module is used to write the report data to a specified file path.

const { getSpeedInsights } = require('@vercel/speed-insights');
const fs = require('fs');

async function saveReportToFile(url, filePath) {
  const report = await getSpeedInsights({ url });
  fs.writeFileSync(filePath, JSON.stringify(report, null, 2));
  console.log(`Report saved to ${filePath}`);
}

saveReportToFile('https://example.com', './report.json');

Other packages similar to @vercel/speed-insights

lighthouse

Lighthouse is an open-source, automated tool for improving the quality of web pages. It can be run as a Chrome Extension or from the command line. It audits performance, accessibility, progressive web apps, SEO, and more. Compared to @vercel/speed-insights, Lighthouse offers a broader range of audits and can be integrated into various CI/CD pipelines.

psi

psi (PageSpeed Insights) is a Node.js module for Google's PageSpeed Insights API. It provides performance reports and suggestions for improving the speed of web pages. While @vercel/speed-insights focuses on Lighthouse metrics, psi directly interfaces with the PageSpeed Insights API, offering a different set of performance insights.

web-vitals

web-vitals is a small, modular library for measuring all the Web Vitals metrics on real users. It is designed to be used in production environments to capture real user performance data. Unlike @vercel/speed-insights, which generates synthetic performance reports, web-vitals focuses on real user monitoring (RUM) to provide insights based on actual user interactions.

README

Vercel Speed Insights

Performance insights for your website

Website · Documentation · Twitter

Overview

@vercel/speed-insights automatically tracks web vitals and other performance metrics for your website.

This package does not track data in development mode.

It has 1st class integration with:

Framework	Package
Next.js	@vercel/speed-insights/next
Nuxt	@vercel/speed-insights/nuxt
Sveltekit	@vercel/speed-insights/sveltekit
React	@vercel/speed-insights/react
Astro	@vercel/speed-insights/astro
Vue	@vercel/speed-insights/vue

It also supports other frameworks, vanilla JS and static websites.

Quickstart

1. Enable Vercel Speed Insights for a project in the Vercel Dashboard.

2. Add the @vercel/speed-insights package to your project

3. Inject Speed Insights to your app

   • If you are using Next.js, React, Nuxt or Vue you can use the framework-specific <SpeedInsights /> component to inject the script into your app.
   • If you are using Sveltekit, you can use the injectSpeedInsights() function @vercel/speed-insights/sveltekit in your top-level +layout.js/ts file.
   • For other frameworks, you can use the inject function add the tracking script to your app.
   • If you want to use Vercel Speed Insights on a static site without npm, follow the instructions in the documentation.

4. Deploy your app to Vercel and see data flowing in.

Documentation

Find more details about this package in our documentation.