System requirements

Functional:

1) Accept input URL and return shortened URL

2)Store short URL to long URL mapping in efficient hash store

3)Duplication and collisions should never be happen

Non-Functional:

1)low latency, user should not notice delay

2)Should scale really well to millions of users

3)Should be cost effective

5)Highlight scalable and consistent

Capacity estimation

Estimate the scale of the system you are going to design...

100 million URL requests a day

API design

front end where to enter log URL and it should return short URL in output box

Database design

Highly efficient hash store and also handles hash collisions

High-level design

1) loadbalancer

2) api gateway

3) Hash store DB

4) Analytics engine

5)CDN to maintain local cash

Request flows

User enters URL in front end, goes to load balancer appropriate api end point passes it to hash DB where long URL is converted to short form and store , key is short URL, value is long URL.

Detailed component design

Hashstore should fast retrieval and collision should be handled,

latency should milli seconds

Underused records should be purged

Trade offs/Tech choices

Redis cache for Hash DB

NGNIX for webserver/API

Failure scenarios/bottlenecks

if some URLs are heavily used and load the system, need to be fault tolerant and highly available, horizontal and vertical auto scaling should be supported

Future improvements

Use AI and ML for recommendation for capacity planing and which ones need to be stored in CDN