Web Crawler System Design
WebCrawlers are used in search engine optimization, mirror site creation, identify copyright infringements.
URL Shortener System Design
URL shortening is used to create shorter aliases for long URLs.
File Storage System Design
Distributed file storage services such as Dropbox/Google Drive System Design
Messenger App System Design
Messaging systems like WhatsApp/Facebook Messenger
Redis GeoHashing
Redis geospatial indexes let you store coordinates and search for them. This data structure is useful for finding nearby points within a given radius or bounding box.