cdnjs is a free distributed JS library delivery service.
JSDelivr is a free public CDN for open-source projects. It can serve web files directly from the npm registry and GitHub repositories without any configuration.
Lodash is a JavaScript library which provides utility functions for common programming tasks using the functional programming paradigm.
Materialize CSS is a front-end framework that helps developers create responsive and mobile-first web applications. It is based on Google's Material Design guidelines.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.