Design URL Link Shortner (like Bit.ly)

Functional Requirements–

1. Users can create a short url from a long url.

1. Optionally support custom alias.

2. Optionally support an expiration time.

2. Users can redirected to the original url from the short url.

Non-Functional Requirements—

1. Low latency on redirects (~200ms)

2. Scale to support 100M DAU and 1B urls

3. Ensure uniqueness of short code

4. High Availability, eventual consistency for url shortening.

Core Entities—

1. Original url

2. Short url

3. User

API–

1. POST /urls → shortUrl

{

originalUrl,

alias?,

expirationTime?

}

2. GET {shortUrl} → Redirect to originalUrl

High-Level Design–