System requirements

Functional:

List functional requirements for the system (Ask the chat bot for hints if stuck.)...

1) When a long url is given as an input it's short alias needs to be returned.

2) Generate a short url

• 62 characters alphanumeric - case sensitive and no special characters
• fixed length for convenience

3) Store the mapping between short url and long url in a store.

Non-Functional:

List non-functional requirements for the system...

• 100K short urls
• 1000 hits per url
• 100 million hits

User growth

• 10% per month - 10K additional urls ; 10X hits

Latency

• Faster redirection - retrieval

Storage

• Proportional to the increasing urls

Concurrency

• heavily concurrent system - scale;

Capacity estimation

Estimate the scale of the system you are going to design...

The system which can handle 100 million hits atleast but which can scale as needed.

API design

Define what APIs are expected from the system...

POST /api/tinyUrl

Host: bloomberg.com

Accept: application/json

Content-Type: application/json

Content-Length:

{

"longUrl": "https://bloomberg.com"

}

GET /api/tinyUrl?shortUrl=https://abcly

Host: bloomberg.com

Accept: application/json

Content-Type: application/json

Content-Length:

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...

A map data store with the short url as the key and long url as the value

short url - string <-> long url - string

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...

The request with a long url from a client goes to the server. Service looks up the database and retrieves if available. Else, returns an error.

For faster retrieval an LRU cache can be maintained before a DB call.

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?