Ever wondered how url shortner works??

clarryson carson — Tue, 26 May 2026 13:01:23 +0000

A URL shortener is a system that converts long URLs into shorter, easier-to-share links. For example, a long URL like https://www.example.com/blog/how-modern-distributed-systems-workcan **become something like **https://sho.rt/aB12x. Behind the scenes, the shortener creates a unique short code and stores it together with the original URL in a database. When someone clicks the shortened link, the server looks up the short code, finds the original URL, and redirects the user to the correct website using an HTTP redirect.

The process is pretty simple.
First, a user submits a long URL to the backend. The backend then generates a unique short code using methods such as Base62 encoding, random string generation, or hashing. After generating the code, the system stores both the short code and the original URL in a database and returns the shortened link to the user.

When the shortened URL is opened, the browser sends a request to the URL shortener server. The server checks the database for the matching short code and responds with a redirect such as 301 Moved Permanently or 302 Temporary Redirect. The browser then automatically navigates to the original website.{Browser → URL Shortener Server → Database Lookup → Redirect}

At small scale, this can work with a simple database and backend server. However, large platforms like Bitly handle billions of redirects daily, so they use advanced technologies such as caching with Redis, distributed databases, load balancers, and analytics systems to improve speed and reliability.

Modern URL shorteners also provide additional features such as click tracking, QR code generation, custom aliases, expiring links, and spam detection. Although URL shorteners look simple on the surface, they are powerful examples of real-world backend engineering because they involve databases, HTTP protocols, caching, scalability, security, and distributed systems. That is why URL shorteners are one of the most popular beginner backend projects and common system design interview questions for software engineers.

DEV Community: clarryson carson

Ever wondered how url shortner works??