Page Speed
Page Speed monitors selected pages for performance regressions and Core Web Vitals changes. Use it to catch slowdowns caused by theme updates, app installs, or code changes before they affect conversion.
Add monitored pages
- Go to Page Speed and click Configure.
- Add the pages you want to monitor — prioritise homepage, collection pages, product pages, and checkout.
- Choose whether to monitor on Mobile, Desktop, or both.
- Save the configuration.
Credit cost: 1 credit per page per device per scan. Monitoring both mobile and desktop doubles the scan cost (e.g. 10 pages on both = 20 credits per scan).
Set up a scan schedule
- On the Page Speed screen, set the scan schedule to at least daily.
- Scans run automatically at the configured frequency.
- You can also click Run Now to trigger a scan manually at any time.
Read scan results
The main Page Speed screen shows:
| Column | What it means |
|---|---|
| URL | The monitored page |
| Score | Overall performance score: green (90–100), orange (50–89), red (0–49) |
| Change | Score delta since the last scan — a negative number means the page got slower |
| LCP | Largest Contentful Paint — above 2.5s impacts conversion; above 4s is critical |
| CLS | Cumulative Layout Shift — measures visual stability |
| Last scanned | When the most recent scan ran |
A warning icon next to a page indicates a significant degradation that requires same-day investigation.
Recent Scans below the table shows a history of scan runs with the number of slowdowns detected.
Investigate a regression
- Click any page row to open the individual page detail.
- Review:
- Historical score trend — a chart showing performance over time.
- Metric breakdown — LCP, CLS, and other Core Web Vitals with historical data.
- Diagnostic signals — data pointing to the likely root cause of the slowdown.
- Correlate the regression date with recent store changes (theme updates, app installs, new scripts).
- Share the historical trend chart with the development team when requesting a fix.
- After a fix is deployed, check this view again to confirm the score has recovered.
AI speed analysis
Shoptest can trigger an AI analysis to help explain a performance regression. Look for the analysis option on the page detail screen.
Credit cost: AI speed analysis uses credits (charged per analysis).
Troubleshooting
Score fluctuates between scans without any store changes
- Minor score variation (1–3 points) is normal and caused by network or server-side variability. Investigate only when the change is significant (5+ points) or sustained across multiple scans.
LCP is above 4s on a product page
- Common causes: unoptimised hero images, render-blocking scripts from third-party apps, or slow server response. Share the diagnostic data with the development team for investigation.
Page Speed shows no data
- No pages have been added for monitoring yet. Go to Configure and add at least one page.