Lighthouse is an open-source automated tool for auditing the quality of web pages. You can perform Lighthouse tests on any web page, and get a series of scores for performance, accessibility, SEO, and more. Every time you run a synthetic test in SpeedCurve, your Lighthouse scores appear at the top of your test results page by default.
Lighthouse scores are different from your other test results
There are a number of reasons why your Lighthouse scores in SpeedCurve might be different from the scores you see in other tools, such as Page Speed Insights. Here are a few common reasons, along with our recommendation not to focus too much on getting your scores to "match".
Lighthouse scores aren't showing up
If you're not seeing your Lighthouse scores, it could be because there are security certificate issues on the page you're testing. If that's the case, then Lighthouse won't run.
To find out what the issue is, click through to your WebPageTest results via the link just below your waterfall chart:
On the WebPageTest results page, click on the Lighthouse Test Log to read the log and find out why the Lighthouse test didn't run.
Gaps in your charts
If you're seeing gaps in your Lighthouse charts, that means we don’t have any data for that metric as part of the test. This is a Lighthouse issue, so we don't have any control over it. When we notice more issues than normal, we pass on bug reports to the Lighthouse team.
If you're concerned about excessive gaps in your data, you can see if your issue is already being discussed in their Github repo, and then you can either ask them directly via GitHub or Twitter (@____lighthouse).
WebPageTest scripts don't work in Lighthouse
Lighthouse doesn't support WPT scripting.
Lighthouse Accessibility scores are provided "as is"
We provide the Lighthouse accessibility scores as part of the overall Lighthouse integration. Accessibility isn't our area of expertise, so we give you those Lighthouse scores and audits "as-is".
Sometimes people ask if the wcag 2.1 is being checked against. According to the Google Lighthouse Github repo, they run both wcag2a and wcag2aatags. This means that the tests check for compliance of A and AA levels.
If you have questions about your Lighthouse Accessibility score, the best option is to contact the Lighthouse team directly. You can see if your issue is already being discussed in their Github repo, and if it's not already there, post your question. Or you could ask them via Twitter (@____lighthouse).
If you have a Lighthouse issue or question that hasn't been covered here, let us know at firstname.lastname@example.org.