Test details
The Synthetic Monitoring test details show the lab results of one page over time, what to fix first, how the page loaded and its console messages.
The Synthetic Monitoring test details show every lab test of one page. Use them to see how the page moved over time, what Lighthouse suggests to fix first, and how the page loaded in one test.
Before you start
- To open the test details, select Synthetic Monitoring in the domain sidebar. Then click a row in the Pages card. See Pages.
- Everyone in the workspace can open the test details. Only owners and admins can change the schedule of the page.
The page header
The header of the Synthetic Monitoring test details shows:
- The breadcrumb: Synthetic Monitoring > Page.
- The page address as the title. In privacy mode, the title is Lighthouse details.
- The schedule chip, for example Daily · 1 location. A paused page shows Paused.
- The Open in… menu. It opens the same page in other modules.
Change the schedule from the header
Owners and admins can change the schedule of the page from the schedule chip.
- Click the schedule chip next to the page title.
- In Frequency, select how often to test the page.
- In Locations, select one or more locations.
- Click Save.
The options depend on your plan. See Pages.
The filter bar
The filter bar of the Synthetic Monitoring test details holds:
- Test run: the test that the page shows. Use the arrows to go to the Older test or the Newer test. Click the date to browse tests by date.
- Device: Phone or Desktop. Each test runs on one device.
- Location: shows when the page has results from more than one location.
- The date range, on the Over time tab only: Last 7 days, Last 28 days, Last 30 days, Last 90 days or Last 6 months. The default is Last 90 days.
The What to fix, How it loaded and Console messages tabs show the selected test. The Over time tab shows all tests in the date range.
The verdict of a test
The verdict at the top of the Synthetic Monitoring test details judges the selected test. A ring shows the Lighthouse score. The headline names the main problem and its key time:
| Headline | Meaning |
|---|---|
| This page loads fast on a slow phone | The score and the main content time are good. |
| Main content takes 4.2 s on a slow phone | The main content (LCP) is not good. |
| Main content shows in 2.1 s on a slow phone, but other checks lower the score | LCP is good, but other measures are not. |
| The screen stays blank for 3.4 s on a slow phone | The first content (FCP) comes late. |
| This page loads slowly on a slow phone / This page could load faster on a slow phone | The score is Poor or Needs improvement. |
For the desktop test, the headline says desktop instead of a slow phone. Hover the ? to see Main content, Blank screen, the real-world LCP, Tested and Device.
Real-world data under the verdict
If the page has a real-world LCP from CrUX Monitoring or RUM Monitoring, the ? of the verdict shows it. If it has none, a line under the verdict says why, or offers to connect RUM Monitoring or CrUX Monitoring. For example, it says Google has not published Chrome data for these pages yet, or offers Set up CrUX Monitoring or Connect RUM Monitoring.
Under the verdict, a Site Health banner shows if Site Health Monitoring found an issue on this page. The line gives the number of open issues. Click Open in Site Health Monitoring to see it.
The tabs
The Synthetic Monitoring test details have up to four tabs:
- Over time: how the results moved over all tests.
- What to fix: Lighthouse opportunities and failed checks of the selected test. The tab shows their count.
- How it loaded: the filmstrip, the final screenshot and the request waterfall of the selected test.
- Console messages: the messages the page wrote to the browser console. This tab shows only when the test logged messages.
Over time
The Over time tab of the Synthetic Monitoring test details has two cards. Each card shows one measure at a time over the tests in the date range. Each number in a tab is the average of the tests in the date range, not the selected test. Click a point in the chart to open that test.
Speed over time
The Speed over time card has these tabs:
| Tab | Measure | Good | Poor |
|---|---|---|---|
| Performance score | The Lighthouse score | 90 or more | under 50 |
| LCP | Largest Contentful Paint | under 2.5 s | over 4 s |
| FCP | First Contentful Paint | under 1.8 s | over 3 s |
| TBT | Total Blocking Time | under 200 ms | over 600 ms |
| CLS | Cumulative Layout Shift | under 0.1 | over 0.25 |
| TTFB | Time to First Byte | under 600 ms | over 1.8 s |
| SI | Speed Index | under 3.4 s | over 5.8 s |
A lab test cannot measure INP, because INP needs real clicks. TBT (Total Blocking Time) is the lab measure closest to INP.
Scores and page weight
The Scores and page weight card has these tabs:
| Tab | Measure | Good | Poor |
|---|---|---|---|
| Accessibility | The Lighthouse accessibility score | 90 or more | under 50 |
| Best practices | The Lighthouse best practices score | 90 or more | under 50 |
| SEO | The Lighthouse SEO score | 90 or more | under 50 |
| TTI | Time to Interactive | under 3.8 s | over 7.3 s |
| Requests | The number of requests | 50 or fewer | over 100 |
| Data transferred | The size of all downloads | 1.5 MB or less | over 3 MB |
What to fix
The What to fix tab of the Synthetic Monitoring test details has two cards.
Opportunities
The Opportunities card lists the changes that Lighthouse expects to make the page faster. The biggest saving is first. Each row shows the time saved on a slow connection, or the size saved (the bytes not downloaded). Open a row to see the files involved.
If there is nothing to fix, the card shows No opportunities found.
Failed checks
The Failed checks card lists the Lighthouse checks that failed in the test. Each check has a category: Performance, Accessibility, Best practices or SEO. Open a row to see what failed and where.
If no check failed, the card shows Every check passed.
How it loaded
The How it loaded tab of the Synthetic Monitoring test details shows the selected test as pictures and as a timeline.
Page load filmstrip
The Page load filmstrip shows the page from left to right, in time. Blank frames in a row mean that visitors see an empty page. Markers show when TTFB, FCP, LCP, SI and TBT happen. The Final screenshot shows the page at the end of the test.
Request waterfall
The Request waterfall shows each request of the page as a bar. The position of the bar shows when the request started. The length shows how long it took. Vertical markers show TTFB, FCP, LCP, DOMContentLoaded and Load.
Above the waterfall, four figures summarize the load:
| Figure | Good | Poor |
|---|---|---|
| Requests | 50 or fewer | more than 100 |
| Transferred | 1.5 MB or less | more than 3 MB |
| Finish | 3 s or less | more than 6 s |
| DOM content loaded | 1.5 s or less | more than 3 s |
Console messages
The Console messages tab of the Synthetic Monitoring test details lists what the page wrote to the browser console in the test. Errors and warnings often mean a broken script or request. Messages that the test browser caused show apart, under their own label.
If the page wrote nothing, the card shows Nothing was logged.
Older tests
VitalSentinel keeps the screenshots, the filmstrip, the request waterfall and the console of a test for 6 months. For an older test, the test details show Limited data for this test. Its scores and checks are still available.
Troubleshooting
Why does the test details page show No tests yet?
If the page shows No tests yet, the first test has not finished. The message says how often the page is tested. Results show as soon as the first test finishes.
Why does it show No tests for this location or device?
If the page shows No tests for this location or device, nothing ran for that combination. Select another Device or Location in the filter bar.
Why are the screenshots or the waterfall missing?
If the page shows Limited data for this test, the test is older than 6 months. VitalSentinel no longer keeps its screenshots, filmstrip, waterfall and console. If the filmstrip shows Screenshots no longer available, the same applies.
Why do the numbers on the Over time tab differ from the selected test?
The numbers in the tabs of the Over time cards are the average of all tests in the date range. The verdict and the other tabs show only the selected test.
Related
- Synthetic Monitoring - lab tests, devices, locations and schedule
- Pages - add, edit and remove tested pages
- RUM Monitoring - the speed of all your own visitors
- Page details in CrUX Monitoring - Google's field data for one page
- Metrics and thresholds - the limits of every measure
