Requirements

Functional Requirements:

List the key functional requirements for the system (Ask the AI for hints if stuck)...

Users can submit a long URL and receive a shortened URL

Users can visit the shortened URL and be redirected to the original URL

Each shortened URL maps to the one original URL

The system should handle invalid/nonexistent short URLs

Non-Functional Requirements:

List the key non-functional requirements (performance, scalability, reliability, etc.)...

The app is read heavy. Creating a shortened URL is a write, but users may click/view shortened URLs many more times.

We cannot lose the mapping between a shortened URL and its original. Losing this mapping means the shortened URL no longer works. We could potentially lose temporary analytics data, such as click counts, if necessary.

Redirects should be very fast, hence, creating a shortened URL can tolerate a higher latency since it happens less often.

We should prioritize low infrastructure cost for an easy design. Start with a simple server and database rather than having expensive components like multiple databases, caches, etc.

Capacity Estimation

Estimate the scale of the system. Consider daily active users, read/write ratio, storage requirements, bandwidth, and any relevant QPS calculations...

API Design

Define the APIs expected from the system. This is your chance to analyze and define the read and write paths so that you can come up with the high-level design...

Two main APIs are needed.

1. Create a shortened URL.

• POST /shorten
• Request: { "url": "https://example.com/very/long/url" }
• Response: { "short_url": "https://tinyurl.com/abc123" }

1. Redirect

• GET /abc123
• Response: HTTP 301 or 302 redirect to the original URL

High-Level Design

Describe the overall system architecture. Identify the main components needed to solve the problem end-to-end. Use the diagramming tool to create a block diagram.

Database Design

Define the data model. Identify the main entities, their attributes, and relationships. Consider the choice of database type (SQL vs NoSQL) and justify your decision based on access patterns...

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.