Friendly Captcha is a proof-of-work based solution in which the user’s device does all the work.
Leaflet is the open-source JavaScript library for mobile-friendly interactive maps.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PHP is a general-purpose scripting language used for web development.
Vue.js is an open-source model–view–viewmodel JavaScript framework for building user interfaces and single-page applications.