System requirements

Functional:

• Redirect Short URL: The system must redirect users from the shortened URL to the original long URL
• Custom Aliases: Users should be able to choose a custom alias for their shortened URL (optional).
• Ability to generate qr code
• Analytics: The system should provide usage statistics for each shortened URL, such as the number of clicks and last accessed time.
• Expiration Management: The service must handle the expiration of short URLs, based on dynamic TTL.
• Batch Creation: The ability to create multiple shortened URLs in a single request.
• Error Handling: The system must handle malformed URLs and provide appropriate error messages.

Rate limitation:

the service will be rate limited using the token bucket algorithm and throttle by endpoints:

The main endpoints (cf API design) free user will have a limit of 100 req/hour and premium 200/hour,if user is reaching the limit to many

time, a notification will be sent to the user by mail.

API Gateaway: Entry point of the service managing auth,rate limiting,load balacing and routing to either the write or read service

AUTH: User will be authenticated with technology like JWT/OAUTH2

Write Service:

Shorten URL:From a long URL return a unique shortened URL, have some restriction : 20 URL generation/per user/30minute

Read Service:

Non-Functional:

Pricing:

Free plan: 30 links max generated and 300 click tracked and one custom domains

paid plan: unlimited

Performance: The service should respond to shortening requests

General constraint :

• within 100 milliseconds, even under a load of 1000 requests per second.
• for short url 70ms and longer 100ms
• for redirecting a short url 60ms and a longer 100ms

Scalability: The system should be able to scale horizontally to handle increased load and volume of URLs without significant degradation in performance.

Availability: The service should have an uptime of 99.9%, ensuring it is available to users most of the time.

Data Consistency: The mapping between shortened URLs and original URLs must be consistent, especially during concurrent access.

Security: The service should implement mechanisms for protecting against malicious use, such as preventing spam or URL abuse.

Maintainability: The codebase should be modular and organized to facilitate maintenance and future feature additions.

Usability: The user interface for shortening URLs should be user-friendly, providing an intuitive experience.

Monitoring: Monitor those metrics:

• Time to redirect ,thresholds: mean 2s
• Number of failed URL generation attempts:
  • threshold: 3/month
• Api response time: should follow the Performance points ,threshold: >100ms/5m

Analystics:

The app will collect usage statics which will be shown to the user

dashboard.

usage statics :

• Click count per short URL:

Track how many times each short URL has been accessed.

• Unique Visitor Count: Count the number of unique users or IP addresses accessing each short URL.
• Geographic Distribution: Log and analyze the geographical location of users accessing a short URL.
• Access Timing: Record the timestamps of when each short URL is accessed to identify peak usage times.
• Referrer URL:Track the URL that led a user to click the short URL (i.e., understanding where traffic is coming from).
• Device and Platform Statistics: Collect data on the types of devices and browsers used to access the URLs, which can help in understanding user demographics.

API design

Overview: The URL Shortener API service consists of three primary components:

1. Auth API:
   • Encapsulates all the business needs to be related to authorization and authentication.
   • Routes:
     • POST /api/auth/login: Authenticate a user and provide access tokens.
     • POST /api/auth/logout: End user session and invalidate tokens.
     • POST /api/auth/signup: Register a new user account.
2. Analytics API:
   • Provides analytics related to the usage of shortened URLs.
   • Routes:
     • GET /api/analytics/url/{id}: Retrieve analytics for a specific shortened URL.
       • Note: This endpoint is accessible only to the owner of the URL.
       • Returns:
         • Success (200): Returns the analytics data for the URL.
         • Unauthorized (401): User not authenticated.
         • Not Found (404): URL does not exist.
3. Shortener API:
   • The main API that provides all capabilities for shortening URLs.
   • Routes:
     • POST /api/shorten: Create a new shortened URL.
     • GET /api/users/{id}/urls: Retrieve all URLs associated with the user.
     • GET /short-url/{short-hash}: Redirect shorten url to true url
     • DELETE /api/shorten/urls/{id}: Delete a specific shortened URL.
     • PUT /api/shorten/urls/{id}: Update a specific shortened URL or its alias.

Overall Design Considerations:

• Each API will implement robust authentication and authorization mechanisms to protect user data.
• Ensure that all endpoints provide clear and consistent error messages to enhance user experience.

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...

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...

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...