System requirements

Functional:

• When the url is opened in a browser, the user is redirected to the correct location in the application
• The URL should persist such that a user could bookmark the shortened URL
• Deep links should be supported, such that URLs can link to "detail" pages vs. surface pages

Non-Functional:

• Shorted URLs will only map to existing URLs already supported in the application
• If the system requires authentication, URLs will only redirect if the user is authenticated
• Shortened URLs will only unfurl in the browser.
• Only generated shorted URLs from the system will be supported
• URLs should be randomly generated to avoid external parties from walking through ids
• URLs will be on a separate domain as the main application
• Each URL will have a short code that maps to the unfurled full route
• There should not be collisions across shortened URL
• Mappings will work across environment, including local development, staging and production
• There will be an index on the mapped url field in the database for quick look ups

Capacity estimation

• Any system generated URL will be supported
• Any requests coming through the browser, and through the service will accurately redirect the user to the correct location

API design

GET /v1/route?{shortedId}

Database design

short_route

long Id

varchar(25) generated_code

varchar(100) mapped_url_path

DateTime CreatedDate

long CreatedByUserId

DateTime UpdatedDate

long UpdatedByUserId

bool IsDeleted

High-level design

• Redirect application with an API and a relational database
• Main application with an API and data storage

Request flows

• Separate repo hosting the application that will mostly behave as a proxy to redirect a user to the main application
• Application will accept requests on the separate domain, will attempt to hit the server. If the user is authenticated the application will hit the API, using a GET request with the unique id that is appended to the main url
• Backend will get the mapped URL, and return it to the front end
• The redirect application will update the URL, in the browser and navigate the user to the main application, adding a cookie for the separate domain

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?