System requirements

Functional:

Functional Requirements:

1. URL Shortening: Users can input a long URL and receive a shortened version.
2. Redirection: Users can access the long URL by entering the short URL in a browser. The service should redirect them to the corresponding long URL.
3. Analytics: Users can see metrics related to clicks on their short URLs, such as the number of times the URL was accessed.
4. Custom URLs: Users have the option to create custom short URLs instead of randomly generated ones.
5. Link Expiry: Users can set an expiry date for their shortened links.
6. User Accounts: Having an optional account system for users to manage their shortened links.

Non-Functional:

1. Performance: The system should handle up to 10,000 URL shortening requests per second.
2. Scalability: The architecture should support scaling to handle increases in traffic without degradation in performance.
3. Availability: The service should achieve high availability, ideally 99.9%.
4. Security: The system should be secure from common vulnerabilities (e.g., SQL injections, XSS) and protect user data.
5. Usability: The user interface must be intuitive and easy to use for the end-users.

Capacity estimation

10,000 RPS means at least 20,000 RPS for checking and creating a short url (means we need a load balancer/request proceeor/gateway)

assume each short url is 8 characters -> 9 bytes per short url

-> 9 * 10000 = 90000 bytes per second -> roughly 9gb per day in just new short urls

assume each short url is 16 characters -> 17 bytes per short url

-> 17 * 10000 = 170000 bytes per second -> roughly 9gb per day in just new short urls -> 17 gb per day in long urls

each URL gets a integer for count metrics -> 4 bytes

Final Capacity per User

User -> user id + 9 + 17 + 4 bytes per user stored

Partion key is User ID -> Sort key is short URL

API design

Define what APIs are expected from the system...

Database design

Use NOSQL database 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?