Requirements

Functional Requirements:

• Create a short URL for a given long URL.
• Return the long URL associated with a given short URL.

Non-Functional Requirements:

• Low latency. We want those urls to be resolved fast.
• Redirection if the id changes from a generated id to a custom-id.
• scalability, How we we resolve urls fast
• High availability
• Not sure the eventual consistency.

API Design

From an API design POV it's quite simple. Let's start with the endpoingt:

• POST /create
  • Body: url, possibly a custom id

High-Level Design

Components needed:

• Client: let say the url shortener's UI
• API
• Database: To store the id, url, redirect

Detailed Component Design

Deep dive into 2-3 key components. Explain how they work, how they scale, discuss tradeoffs, capacity, and any relevant algorithms or data structures.