Apache is a free and open-source cross-platform web server software.
Leaflet is the open-source JavaScript library for mobile-friendly interactive maps.
Next.js is a React framework for developing single page Javascript applications.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Phusion Passenger is a free web server and application server with support for Ruby, Python and Node.js.
Unpkg is a content delivery network for everything on npm.