System requirements

Functional:

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

UI

• Login
• Enter a URL and get a short URL
• Must be unique
• Avoid characters that could be confused
  • Alway lowercase, eliminate numbers that could be confused with letters
    • l and 1
    • o and 0
    • g and 9
• View list of short urls
  • Statistics
    • Clicks/time
    • Clicks/referrers
• Delete a short url
• Update long url

Service

• Short URL redirect to the long URL

Track analytics

• date/time
• count
• referrer

Non-Functional:

List non-functional requirements for the system...

Performance: TBD requests/second

Reliability: Aim for 100% uptime, deployment should not cause downtime

Scalability: Automatic scaling to handle traffic spikes

Capacity estimation

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

• How many users?
  • How many concurrently using the service?
• How many urls/user?
• How many clicks on a short url?
  • How many concurrent?

API design

Define what APIs are expected from the system...

Create short URL

Endpoint: POST /short

Authentication: Session

Body:

{

"url": ""

}

Response:

{

"shortUrl": ""

}

Get short URLs

Endpoint: GET /short?max={max}&offset={offset}

Params:

• max - Number of urls to return
• offset - Paging offset

Response:

[

{

shortUrl: "",

longUrl: ""

},

...

]

Redirect short URL to long URL

Endpoint: GET /{shortUrl}

Response: Redirects to the long URL

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...

Table: url_mapping

Columns:

id - unique id (auto-generated primary key or other unique id, e.g. ObjectId if Mongo)

customer_id - foreign key to the customer

short_code - the unique short code to go at the end of the url

url - the original url to redirect to

dateCreated - date the record was created

lastUpdated - date the record was last modified

Table: metrics

id - unique id

short_code - the short code

date_clicked - date the url was clicked

referrer - referrer url if it was provided

Table: customer

id

email

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?