Lighthouse Lite Audit

About this tool

Lighthouse Lite Audit fetches Lighthouse scores for any public webpage via the Google PageSpeed Insights API. Enter a URL, choose mobile or desktop strategy, and get four animated score circles for Performance, SEO, Accessibility, and Best Practices — each colored green (≥90), orange (50-89), or red (<50) to make problem areas immediately obvious. Below the scores, the top 10 failing audits are listed with titles and one-sentence fix descriptions, giving you a prioritized list of improvements. You can download the full audit data as a JSON report for offline analysis or to share with your team. All analysis is done by Google's infrastructure, so results match what you'd see in Chrome DevTools Lighthouse panel.

Why use it

• Instant Lighthouse scores without opening Chrome DevTools or installing a CI plugin.

• Mobile and desktop strategies match Google's real crawl and ranking signals.

• Color-coded score circles make performance bottlenecks visible at a glance.

• Top issues list prioritizes the biggest wins so you know where to focus first.

• JSON report download enables team sharing and automated tracking over time.

• Powered by the official Google PageSpeed Insights API — same data as Search Console.

How to use

1. Enter the full URL of the page you want to audit — must be publicly accessible from Google's network.
2. Choose Mobile or Desktop strategy — mobile is the default as Google uses mobile-first indexing.
3. Click Run Audit. Results typically arrive in 10-30 seconds while PageSpeed Insights processes the page.
4. Review the four score circles for Performance, SEO, Accessibility, and Best Practices.
5. Scroll down to see the top 10 failing audits with descriptions.
6. Click Download JSON Report to save the full audit data for offline review.

When it helps

• Checking a client's website before and after an optimization sprint to demonstrate measurable improvement
• Auditing Core Web Vitals before a major deploy.
• Identifying accessibility issues before a public launch.
• Comparing mobile vs desktop performance gaps on a responsive site.
• Quick sanity-check after adding third-party scripts that may slow load time.

Examples

URL: https://example.com
Strategy: Mobile

Performance: 72 (orange)
SEO: 95 (green)
Accessibility: 88 (orange)
Best Practices: 92 (green)
Top issue: Reduce unused JavaScript (saves 1.2s)

URL: https://app.example.com
Strategy: Desktop

Performance: 41 (red)
SEO: 60 (orange)
Accessibility: 78 (orange)
Best Practices: 83 (orange)
Top issue: Avoid an excessive DOM size (4500 nodes)

URL: https://news.example.com/article-slug
Strategy: Mobile

Performance: 58 (orange)
SEO: 100 (green)
Accessibility: 91 (green)
Best Practices: 75 (orange)
Top issue: Properly size images (saves 850 KB)

Tips

• Mobile strategy uses simulated 4G throttling (1.6 Mbps down, 750 Kbps up) and 4× CPU slowdown — desktop is unthrottled.
• Lab metrics (LCP, FCP, TBT, CLS) shown here differ from field metrics (CrUX) — both matter, but field data is what Google ranks on.
• Score 90+ is 'Good', 50-89 'Needs Improvement', <50 'Poor' per Google's official thresholds.
• JSON reports include the full Lighthouse v10+ output — feed them into lighthouse-budget or custom dashboards for trend tracking.
• Re-running back-to-back can produce slightly different scores due to network and CPU variance — average 3-5 runs for reliable numbers.
• Pages behind A/B tests may score differently each run if variants have different bundle sizes or render strategies.
• Improving Performance often improves SEO indirectly: faster pages get crawled more deeply and ranked better.

Frequently Asked Questions

Glossary

Lighthouse

Google's open-source automated tool for auditing web page quality across performance, SEO, accessibility, and best practices, available in Chrome DevTools and as a Node.js CLI.

Core Web Vitals

Google's set of three user-experience metrics — LCP, INP (formerly FID), and CLS — that affect search ranking since 2021.

LCP (Largest Contentful Paint)

The time from navigation start until the largest text or image element in the viewport is rendered. Good: ≤2.5s. Poor: >4.0s.

FID (First Input Delay)

The delay between a user's first interaction (tap, click, key) and the browser's response. Replaced by INP in 2024 but still in older reports. Good: ≤100ms.

INP (Interaction to Next Paint)

The 75th-percentile latency of all user interactions on the page during its lifetime. Replaces FID. Good: ≤200ms.

CLS (Cumulative Layout Shift)

A unitless score measuring how much visible content shifts unexpectedly during page load. Good: ≤0.1. Poor: >0.25.

FCP (First Contentful Paint)

The time from navigation start until the first text, image, or non-white pixel is painted. Good: ≤1.8s.

TBT (Total Blocking Time)

The total time the main thread was blocked (>50ms tasks) between FCP and TTI, in milliseconds. A lab proxy for INP.

TTI (Time to Interactive)

The point at which the page is fully interactive — main thread is idle for ≥5 seconds and most resources have loaded.

Headless Chromium

The Chrome rendering engine running without a UI — Lighthouse uses it to load the page, simulate device conditions, and collect metrics.

PageSpeed Insights (PSI)

Google's web service that runs Lighthouse against any public URL and returns scores plus field data from CrUX.

CrUX (Chrome User Experience Report)

A public dataset of real-user performance data from opted-in Chrome users, used by Google for Core Web Vitals ranking signals.