System requirements

Functional:

The URL shortening service should

• generate short urls for a longer url, that can be accessed by anyone with a short URL.
• support up to 1500 characters in length.
• persist the URLs for 30 days. The short URLs should be deleted from database after 30 days.

Non-Functional:

The URL shortening service should

• be able to handle 500 transactions per second in normal state and 1000 transactions per second in peak state.
• ensure 99.99% uptime.
• redirect users in less than 200 millisecond.

Capacity estimation

The URL shortening service should support 500 transactions per second in normal state and 1000 transactions per second in peak state.

The system should also be able to designed to have 100,000 users, with each user generating 5 short URLs per day, amounting to 15 million short URLs generated each month. The design needs to ensure enough storage capacity to store all the short URLs, along with the relevant metadata.

API design

The URL shortening service should have following APIs

• generateShortURL(String longUrl): String shortUrl
• getLongURL(String shortUrl): String longUrl

Database design

Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...

High-level design

You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design. If you are unfamiliar with the tool, you can simply describe your design to the chat bot and ask it to generate a starter diagram for you to modify...

Request flows

Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...

Detailed component design

Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...

Trade offs/Tech choices

Explain any trade offs you have made and why you made certain tech choices...

Failure scenarios/bottlenecks

Try to discuss as many failure scenarios/bottlenecks as possible.

Future improvements

What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?