Requirements

Functional Requirements:

• Create a short URL for a given long URL.
• Return the long URL associated with a given short URL.

Non-Functional Requirements:

• The system shall maintain high availability, ensuring service is available at all time, even during peak traffic and outages
• The redirect latency should be minimal, less than 50 ms
• Frequently accessed short URL should be cached to optimize performance
• Utilize a CDN to distribute cached URLs across multiple regions

API Design

There needs to be below API endpoint -

Endpoint - api/v1/shorten

HTTP Request - POST

Json Body - { "url" : "www.example.com" }

Response -

Status Code - 201

{

shortenUrl : "tiny.ly/{shortCode}"

}

Endpoint - /{shortCode}

HTTP Request - GET]

Response -

Status Code - 302

Redirect Url - www.example.com

High-Level Design

Load Balancer - There needs to be distribution of load among multiple servers. This will act as the entry point for the request and will route to the ideal server for reducing the latency.

Services - There are two API services available to enable the functionality -

1. Write Service - To be used for creating a tiny link based on the provided link
2. Read Service - To be used to fetch the original link and redirect based on the provided short code

Cache - Redis or similar cache mechanism needs to be implemented to cache the frequently accessed links.

Database - Need to use NoSQL database for easier read as the read service would be the more frequently used service.

Analytics Service - A analytics job needs to be configured to figure out the region, demographic and rate of click. This will be vital for collecting necessary analytics data.

Detailed Component Design

Cache - The caching will be the vital service to enable low latency redirection. An algorithm needs to be implemented to determine a popularity score of a link. The analytics service would be useful for determining the popularity score. Based on the time when the users access the link, the region, and number of requests.

Database - The database needs to be sharded across cloud regions to reduce latency and database read time. Based on the geo-location of the link creator, the particular sharding region needs to be determined for storage.