GTmetrix is a free tool to test and monitor your page's performance. Using Lighthouse, GTmetrix generates scores for your pages and offers actionable recommendations on how to optimize them.
gtmetrix.com appears in the published seller files of 1 advertising network. Each row below is that network's own declaration that it is authorised to sell this site's inventory, with the date the relationship first appeared in the record.
Same niche, closest authority score — the competitive set a network would compare gtmetrix.com against.