System requirements

Functional:

• a shortened url relative to the URL provided
• the URL should redirect to the original URL provided
• the link should track statistics, like number of clicks
• users can tweak the alias of the shortened URL
• users can set an expiration date for the shortened url

Non-Functional:

• number of requests per second handled
• can scale up to handle additional requests
• is available a certain amount of time; 99.9% at a minimum
• ensure that URLs are safe and protected from unauthorized access
• the link shortener should be easy to use and understand for all user levels

Capacity estimation

I anticipate that this system will have about 1000 users per month. Each user will on average need to generate about 5 shortened urls per week, or roughly 20 urls per user, equaling 20000 requests for url shortening. Assuming most of the load will happen during business hours Mon-Fri, this comes out to about 1000 requests per day.

API design

We'll start with the following endpoints:

• /get/{url_id} to retrieve a shortened url that's already been created
• /get to retrieve all shortened_urls for an account
• /post to create a new shortened_url; this will take the full url as part of the body

Database design

tables:

• urls
  • id
  • account_id
  • user_id
  • original_url
  • shortened_url

High-level design

flowchart TD A[Client] -->|HTTP Request| B[API] B -->|Route based on Endpoint| C{Request Type} C -->|POST| D[Shorten URL Logic] D --> E[Store URL in Database] E -->|Return Shortened URL| F[API Response] C -->|GET| G[Redirect to Original URL] G -->|Get Original URL| E

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?