Cloudinary is an end-to-end image- and video-management solution for websites and mobile apps, covering everything from image and video uploads, storage, manipulations, optimisations to delivery.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
PHP is a general-purpose scripting language used for web development.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.