How URL Shorteners Work

URL shorteners operate using a simple but powerful concept: key-value mapping. When you create a short link, the service generates a unique identifier and stores it alongside the original destination URL.

The Process

1. You submit a long URL to the shortener service.
2. The service generates a unique slug (e.g., abc123).
3. The slug and destination URL are stored in a database.
4. When someone visits onlineurlshortner.com/abc123, the server looks up the slug.
5. The server returns an HTTP redirect response pointing to the original URL.

301 vs 302 Redirects

There are two main types of HTTP redirects used by URL shorteners:

• 301 (Permanent): Tells browsers and search engines the content has permanently moved. This passes most of the SEO value (link equity) to the destination URL.
• 302 (Temporary): Tells browsers the redirect is temporary. Search engines may keep the original URL in their index.

Most URL shorteners use 301 redirects by default because they preserve link equity and provide a better user experience.

What Happens When You Click a Short Link?

When you click a short link, your browser sends a request to the shortener's server. The server looks up the slug, finds the destination URL, and returns a redirect response. Your browser then automatically navigates to the destination. This entire process typically completes in milliseconds.