Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
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.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Leaflet is the open-source JavaScript library for mobile-friendly interactive maps.
Liberapay is a non-profit organisation subscription payment platform.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.