CWV Monitoring
🔧 Quick Info: CWV Monitor automatically runs daily Lighthouse performance tests on the public storefront URLs you choose. It saves the results and charts your scores over time so you can spot performance changes and confirm whether optimizations are working.
What It Does
CWV Monitor keeps an automated watch on the speed, usability, and technical health of your storefront pages.
You choose the public URLs you want to monitor and the time of day each daily check should run. Once configured, the tool tests every monitored page once a day using Google’s PageSpeed Insights and Lighthouse testing engine.
Each monitor watches one URL. You can create separate monitors for important pages such as:
- Your home page.
- A high-traffic category or collection page.
- A best-selling product page.
- A landing page used for advertising campaigns.
- A recently redesigned or optimized page.
Each daily report records the following Lighthouse category scores on a scale from 0 to 100:
- Performance
- Accessibility
- Best Practices
- SEO
- PWA
The report also includes important loading and layout metrics:
- First Contentful Paint
- Speed Index
- Largest Contentful Paint (LCP)
- Total Blocking Time (TBT)
- Cumulative Layout Shift (CLS)
Historical Reporting: Because the test runs every day, each monitor builds a history of its scores. The report page charts Performance, Accessibility, Best Practices, and SEO so you can see changes over time.
This makes it easier to see whether a theme update, newly installed app, large image, tracking script, or other storefront change affected performance.
CWV Monitor works the same way for BigCommerce and Shopify stores. The test runs from outside the storefront, just as a visitor or search engine would access it, so there is nothing to install in your theme.
When Should You Use This?
- You want to monitor Core Web Vitals and Lighthouse scores without running manual tests every day.
- You are launching a new theme and want before-and-after performance results.
- You are optimizing images, scripts, apps, or storefront code.
- You want to confirm that a performance improvement had a measurable effect.
- You want to catch unexpected drops in Performance, Accessibility, Best Practices, or SEO scores.
- You want separate monitoring for your home page, category pages, product pages, or campaign landing pages.
- You want a simple performance history that can be reviewed from your dashboard.
- You manage either a BigCommerce or Shopify store and want the same monitoring process across platforms.
Before You Get Started
- Your BigCommerce or Shopify store must be connected.
- Your plan must include CWV monitoring.
- Your plan determines how many monitors you can create.
- Each monitor watches exactly one public URL.
- The monitored page must be reachable from the public internet.
- The page cannot be password-protected or hidden behind a maintenance page.
- Decide what time of day the daily report should run.
- Daily run times use your store’s timezone.
Plan Feature: CWV Monitor appears in the navigation only when your current plan includes CWV monitoring.
Public Pages Only: Lighthouse must be able to open the URL without signing in. Password-protected storefronts, preview pages, and maintenance pages cannot be monitored successfully.
How to Use It
1 Open CWV Monitor
Open CWV Monitor from the navigation.
If the option does not appear, your current plan does not include CWV monitoring.
2 Create a Monitor
Select Create to add a new monitor.
The Create button is unavailable when you have reached the monitor limit included with your plan.
3 Enter a Name
Enter a descriptive name for the monitor so you can identify it easily in the monitor list.
Examples include Home Page, Top Category, or Best-Selling Product.
4 Enter the Public URL
Enter the complete public URL of the page you want to monitor.
Each monitor accepts one URL. Create additional monitors for other pages you want to track.
5 Choose the Daily Run Time
Use Sync Daily At to choose the hour when the daily report should run.
The selected time uses your store’s timezone.
6 Save the Monitor
Save the monitor to begin tracking the URL.
The first report runs immediately. After that, the monitor runs once each day at the selected time.
First Report: You do not need to wait until the scheduled daily time for the first test. Saving a new monitor starts its first report immediately.
7 Review the Monitor List
The monitor list displays the following information for each monitor:
- The monitored URL.
- The daily run time.
- The date and time of the last completed run.
- The latest Performance score.
- The latest Accessibility score.
- The latest Best Practices score.
- The latest SEO score.
A newly created monitor displays Report has not been run yet until its first test is complete.
8 Open the Report Page
Select a monitor to open its full report page.
The report page displays the latest category scores, Core Web Vitals and lab metrics, and the historical trend chart.
[Screenshot: Monitor report page showing category scores, metrics, and the history chart]
9 Review the Dashboard Summary
Your store dashboard includes a CWV summary card showing the latest scores at a glance.
Open the full monitor report when you need the detailed metrics or historical trends.
Field Reference
| Field | Required? | Notes |
|---|---|---|
| Name | Yes | A descriptive label used to identify the monitor. Maximum length is 255 characters. |
| URL | Yes | The complete public URL that will be tested. Each monitor accepts one URL. Maximum length is 255 characters. |
| Sync Daily At | Yes | The hour when the daily Lighthouse test runs. The time uses your store’s timezone. |
Category Scores
| Score | What It Measures |
|---|---|
| Performance | How quickly the page loads and becomes usable in the Lighthouse test environment. |
| Accessibility | Automated checks for common accessibility issues in the page’s markup and interface. |
| Best Practices | Checks for common security, browser, and development best-practice issues. |
| SEO | Automated checks for basic technical search-engine optimization requirements. |
| PWA | Checks related to Progressive Web App capabilities and requirements. |
Performance Metrics
| Metric | What It Represents |
|---|---|
| First Contentful Paint | How long it takes before the browser displays the first visible piece of page content. |
| Speed Index | How quickly the visible parts of the page are displayed during loading. |
| Largest Contentful Paint (LCP) | How long it takes the largest visible content element to finish rendering. |
| Total Blocking Time (TBT) | How long the page’s main browser thread is blocked and unable to respond quickly to input during the lab test. |
| Cumulative Layout Shift (CLS) | How much visible content unexpectedly moves while the page is loading. |
Understanding TBT and INP
CWV Monitor reports Total Blocking Time rather than Interaction to Next Paint.
The reports are Lighthouse lab tests. TBT is the Lighthouse lab metric used to estimate how responsive a page is while loading.
Interaction to Next Paint, commonly called INP, is based on interactions from actual visitors and requires real-user field data. It is not included in these automated Lighthouse reports.
Lab vs. Field Data: CWV Monitor shows controlled Lighthouse lab results. These are useful for tracking technical changes, but they are different from the real-user field data collected from visitors over time.
Using the History Chart
The report page charts the following scores over time:
- Performance
- Accessibility
- Best Practices
- SEO
Use the chart to look for patterns and changes rather than focusing on one isolated result.
For example, you may see:
- A Performance decline after installing a new storefront app.
- An improvement after compressing large images.
- A score change after launching a new theme.
- A temporary dip caused by normal test-to-test variation.
Watch the Trend: Lighthouse scores can vary between individual runs. A consistent change over several days is generally more useful than comparing two isolated tests.
Report History
Daily CWV reports are retained for approximately one month.
The history chart displays the reports that are still available within that retention period. Older reports are removed as new daily reports are added.
Troubleshooting and FAQ
CWV Monitor does not appear in the navigation
Your current plan does not include CWV monitoring. Review your plan or upgrade to enable the feature.
The Create button is missing or I cannot add another monitor
You have reached the number of monitors included with your plan.
The tool may display the following message:
You have reached the limit of cwv monitoring. Please upgrade your plan to create more reports.
Upgrade your plan to add more monitors.
Where is INP?
CWV Monitor runs Lighthouse lab tests, which report Total Blocking Time as the interactivity metric. INP depends on interactions collected from actual visitors and is not included in these reports.
My scores differ from Chrome or PageSpeed Insights
Lighthouse lab scores can vary from one run to another because of differences in timing, server response, network conditions, and the test environment.
Use the daily trend to identify consistent changes instead of expecting every single test to return the same score.
How long is report history kept?
Daily reports are kept for approximately one month. The history chart displays the reports that are still on record.
Will I receive an alert when a score drops?
No. CWV Monitor records and charts the results but does not send alert emails when a score decreases.
Review the dashboard summary card or open the monitor’s report page to check the latest results.
The first report has not appeared yet
The first test begins immediately after the monitor is saved, but the Lighthouse audit still needs time to finish. Until it completes, the monitor displays Report has not been run yet.
The monitored page cannot be tested
Confirm that the URL is correct and publicly available. Pages behind a password, login, maintenance screen, or private preview cannot be audited successfully from the public internet.