Introduction
Typically, a long URL is a system-generated URL, usually containing multiple query parameters that may be encrypted/encoded to mask those parameters. The need for shortened URLs arises when long URLs have to be shared for various purposes, like sharing links via SMSs, Emails, media types, like Twitter or WhatsApp, etc.
A URL shortening service might sound like a simple service at first, but it poses a very interesting and challenging engineering problem. Please pause here and think about how you could design a system to generate an infinite number of short URLs for possibly all long URLs in the world. The interesting part of the problem is generating unique, random identifiers for these long URLs. The identifiers should be short enough to fit in the URL with an acceptable character set.