PageSpeed Insights vs WebPageTest for speed work:

PageSpeed Insights vs WebPageTest for speed work:
I profiled the same slow page in both back to back.

PageSpeed Insights
➕ One score, CrUX field data + Lighthouse lab in a single view
➕ Zero setup; perfect for a quick verdict or client screenshot
➖ Single run, single location, no filmstrip — shallow for real debugging

WebPageTest
➕ Filmstrip + waterfall + multiple runs from chosen locations/devices
➕ Connection throttling shows your real mobile-3G experience
➖ Slower, more knobs; overkill for a quick check

Best for: a fast pass/fail + field data → PSI. Actually hunting the bottleneck → WebPageTest.

Price-vs-value: both free. PSI told me the page was slow; WebPageTest's waterfall showed a render-blocking font swap PSI never surfaced. Diagnose deep in WPT, report in PSI.

Pick PSI for the verdict. Skip it for diagnosis — the waterfall lives in WebPageTest.

Profiled on a real, live page.