Ahrefs is an online toolset utilised for search engine optimisation (SEO) and competitor analysis, which permits users to analyse their website's performance, track keyword rankings, identify backlink opportunities, and research competitors' websites, among other features.
Apache is a free and open-source cross-platform web server software.
Calendly is an app for scheduling appointments, meetings, and events.
cdnjs is a free distributed JS library delivery service.
Google AdSense is a program run by Google through which website publishers serve advertisements that are targeted to the site content and audience.
Open Graph is a protocol that is used to integrate any web page into the social graph.