Apache is a free and open-source cross-platform web server software.
D3.js is a JavaScript library for producing dynamic, interactive data visualisations in web browsers.
Debian is a Linux software which is a free open-source software.
Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Google Analytics is a free web analytics service that tracks and reports website traffic.
Leaflet is the open-source JavaScript library for mobile-friendly interactive maps.
Unpkg is a content delivery network for everything on npm.