CrUX Monitoring

Chrome User Experience Report (CrUX) provides real-world performance data collected from Chrome users who have opted into sharing usage statistics. This is the same data Google uses for search ranking.

What is CrUX?

CrUX is a public dataset of real user experience data collected by Google Chrome. It includes:

• Core Web Vitals metrics (LCP, CLS, INP)
• Navigation metrics (TTFB, FCP)
• Data from millions of Chrome users worldwide
• 28-day rolling aggregates

Why CrUX Matters

Google Search Ranking

Google uses CrUX data as a ranking factor. Sites with good Core Web Vitals get a ranking boost in search results. CrUX is the definitive source for this evaluation.

Real User Data

Unlike lab tests, CrUX shows actual user experiences:

• Real devices and networks
• Real geographic distribution
• Real user behavior patterns

Comparison with RUM

Using CrUX in VitalSentinel

Adding URLs

Navigate to your domain's CrUX Monitoring section and click Manage Pages. You'll see two tabs:

Manual tab:

1. Enter pages in the text area (one per line for bulk import, or a single page)
2. Click Add page (or Add pages for multiple)

Sitemap tab:

1. Shows pages discovered from your sitemap scan
2. Click Track all sitemap pages to monitor all discovered pages at once
3. Pages already being monitored are automatically skipped

URL Data Status

Each monitored page shows one of three states, so you can tell at a glance whether CrUX has data for it yet:

Pages showing No data yet are still worth keeping if you expect traffic to grow - the moment they cross Google's threshold, metrics start appearing. Pages Awaiting first collection usually pick up data after the next weekly collection.

Available Metrics

For each URL, you'll see:

Mobile vs Desktop

CrUX data is broken down by form factor:

• Mobile - Phones and small tablets
• Desktop - Laptops and desktop computers

Each has separate thresholds and data, as mobile performance typically differs from desktop.

Percentile Values

VitalSentinel displays the 75th percentile (P75) value for each metric. This means 75% of your users experience this value or better.

The P75 is the industry standard for Core Web Vitals assessment and is what Google uses for search ranking.

Assessment Status

Each metric shows an assessment based on the P75 value:

Distribution View

The distribution chart shows what percentage of users fall into each category:

• Green (Good) - Experiences meeting the threshold
• Yellow (Needs Improvement) - Experiences in the middle range
• Red (Poor) - Experiences not meeting the threshold

Trend Indicators

Each metric shows whether performance is:

• Improving - Getting better over time
• Declining - Getting worse over time
• Stable - No significant change

Detailed Breakdowns

Opening a monitored page reveals deeper CrUX breakdowns beyond the headline metrics:

• Core Web Vitals trends over time, per metric
• Performance and device distribution across your users
• Navigation types (how users arrived at the page)
• Round-trip time (network latency to your users)
• LCP resource types and image subparts (what the largest element is and where its load time goes)

CrUX vs Your RUM Data

You might notice differences between CrUX and your RUM data:

CrUX may differ because:

1. Chrome only - CrUX excludes Safari, Firefox, Edge users
2. Opt-in users - Only Chrome users who share statistics
3. 28-day aggregate - Smooths out daily variations
4. Different sampling - Google's sampling may differ from yours

When to use which:

• CrUX - For SEO evaluation and Google ranking assessment
• RUM - For detailed debugging and all-browser coverage

Eligibility for CrUX

Not all URLs have CrUX data. Requirements:

1. Publicly accessible - URL must be indexable
2. Sufficient traffic - Enough Chrome users visiting
3. Not blocked - robots.txt must allow indexing

Origin vs URL Data

CrUX provides two levels of data:

Origin Level

Aggregated data for your entire domain (e.g., https://example.com), labeled Whole Site in the page list.

• Always available if you have any traffic
• Represents overall site health
• Good for monitoring your homepage and main landing pages

URL Level

Specific page data (e.g., https://example.com/products/widget)

• Requires significant traffic to that URL
• More granular insights
• Useful for key pages

Historical Trends

VitalSentinel tracks CrUX data over time:

• Weekly snapshots stored
• Trend charts showing improvement/regression
• Compare current vs previous periods

Improving CrUX Scores

Since CrUX is a 28-day aggregate:

1. Make improvements to your site
2. Wait 4-6 weeks for data to reflect changes
3. Monitor RUM for immediate feedback
4. Check CrUX for Google's view

Priority Order

Focus on metrics in this order:

1. LCP - Biggest impact on user perception
2. INP - Critical for interactivity
3. CLS - Visual stability

Related Features