System requirements

Functional:

1. generate tiny url based on user inputs
   1. user inputs a original url
   2. check for existing url
   3. i. return existing url, return;
   4. ii. there is no existing url, send request to url generation service
   5. generate short code
   6. store generated shorten url and original url to database
   7. if success, return shorted url
2. use tiny url and redirect to the page
   1. query the tiny url in the database
   2. if exists redirect to original url
   3. if not return error
3. Expiration: Option to set an expiration date for the shortened URLs.
4. Bulk URL Shortening: Allow users to shorten multiple URLs at once.

Non-Functional:

1. High availability, as user expect to get an instant results.
2. We also want to make sure there is low latency, for instant results.

Capacity estimation

10k DAU *5 request per day = 50 k request/86400 s

original URL size 100*1bytes = 100bytes

Tiny url size 10 bytes

metadata 50 bytes

storage needed = 50k*160bytes*5years*365 = 15GB

qps for url redirect = 100 k / 12 / 3600 = 2 request/ sec

API design

external APIs:

GET getTinyURL(original_url, user_token)

• return tiny_url

GET redirectToPage(tiny_url, user_token)

• Redirect to original url
• Exception tiny_url not found

Database design

key-value store:

• key: tiny_url
• value:
  • original_url,
  • user
  • timestamp
  • expiration

reverse key-value store:

• key: original_url
• value:
  • tiny_url

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?