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SiteRune vs GTmetrix and WebPageTest
· Configuration notes, not a newsroom.
Filmstrip tools run a browser. SiteRune does not. Use them for LCP waterfalls. Use SiteRune for TTFB from this vantage point, cache headers, and the CMS punch list.
Lab Chrome vs a fetch
GTmetrix and WebPageTest execute the page, block third parties, show waterfalls. That is how you debug a hero image. SiteRune records TTFB of the HTML fetch and whether Cache-Control is no-store. No INP. No filmstrip.
Order of operations
If TTFB is 2s on SiteRune, the filmstrip is a funeral. Cache the document, then go to WebPageTest. If GPTBot is banned, the filmstrip will not tell you. Different instruments.
Run it on a live URL
The brief will name your CMS and attach the files. Three guest scans, no card.