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: People want to get the link in instant.
• Security: Links might contain keys or other sensitive data. The attack surface must be reduces to avoid leaking all existing full urls.
• Storage: SQL table with proper indexing.

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...

High-Level Design

Tiny url is a pretty thin system that accepts any browser url and returns short url link as an output.

Step by step flow:

1. A client send a request via WEB UI that gets propagated to the server.
2. Server validates the link, making sure it has the right format and filters it out from SQL injections.
3. If link is correct, create new entry in the database where columns could be:
   1. Full url link
   2. Short link
   3. Created at
4. If creation was successful and new database entry created, respond with the shortened link to the client. If not, return an error message.
5. Display new link on the client side.

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.