Does your site score at least 90 out of 100 on Lighthouse mobile performance?
Lighthouse simulates a slow mobile network to predict whether AI agents will time out on your site.
What this signal tests
We run Google's Lighthouse performance audit through the PageSpeed Insights API in mobile mode. Lighthouse loads your page in a controlled lab environment that simulates a mid-tier mobile device on a throttled network, then scores the result from 0 to 100. We require a score of 90 or higher, the threshold Google labels as good.
Why it matters for your visibility in AI
Lighthouse is the closest available proxy for how an AI agent browser will experience your site before it has enough real-user data to judge. If Lighthouse already says your page is slow on a simulated mid-tier phone, an agent running Chromium with strict per-action timeouts will struggle even more, because it adds its own automation overhead on top. A failing Lighthouse score also tells you exactly what is wrong. The report flags render-blocking scripts, unused JavaScript, oversized images, and missing compression as named audits, each with a remediation hint. Fixing them improves the experience for AI agents, mobile users, and Google rankings in one pass, which is rare leverage.
Pass criteria at a glance
| Criterion | Passes when |
|---|---|
| performance score >=0.90 on mobile. |
How we test it
We call Google's PageSpeed Insights API with your URL and the mobile strategy, requesting only the performance category. The API runs Lighthouse against your page in a Google-hosted lab environment and returns a JSON report. We read the numeric performance score, which ranges from 0 to 1, and pass the signal if the score is 0.90 or higher.
Show technical detection method
GET https://www.googleapis.com/pagespeedonline/v5/runPagespeed?strategy=mobile&category=performance; read lighthouseResult.categories.performance.score.
If your site fails: how to fix it
- Open the Lighthouse report in PageSpeed Insights or Chrome DevTools and read the Opportunities section. Each audit lists the estimated saving and a remediation guide - work top down by impact.
- Eliminate render-blocking resources by adding defer or async to non-critical scripts, and inlining critical CSS. Move third-party tags such as analytics and chat widgets to load after first paint.
- Reduce image weight by serving modern formats (AVIF, WebP) with responsive srcset, and let a CDN such as Cloudflare Images, Vercel Image, or AWS CloudFront with Lambda@Edge handle resizing automatically.
- Enable text compression (Brotli or gzip) at your origin or CDN. This is usually a one-line config change with a large impact on score.
- Tree-shake unused JavaScript: remove unused dependencies, code-split routes, and load heavy components only when needed. Bundle analyzers in Webpack, Vite, or Rollup pinpoint the worst offenders.
Quick facts
| Maturity | ESTABLISHED |
|---|---|
| Weight | medium |
| Category | Performance |
Primary sources
Related signals
Frequently asked questions
How fast does my site need to be?
A Lighthouse mobile performance score of 90 or higher is the published Google threshold for good. Scores between 50 and 89 are needs improvement; below 50 is poor. Aim above 90 to leave headroom for measurement variance.
Why does my score change every time I run it?
Lighthouse simulates network conditions and CPU throttling, and small variance is normal. Run the test three times and take the median to get a stable reading. Major drops typically indicate a real regression rather than noise.
Do I need to pass on both mobile and desktop?
Mobile is the stricter benchmark and the one Google emphasises through mobile-first indexing. If you pass mobile at 90, desktop almost always exceeds 95. AI agent browsers also often emulate mobile viewports.
Will fixing this also improve my Google ranking?
Indirectly, yes. Lighthouse itself is not a ranking factor, but the underlying metrics it measures (LCP, INP, CLS) are. Fixing Lighthouse issues almost always improves real-user Core Web Vitals, which is a ranking factor.
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