What is a URL shortener and how does it actually work?
A short link is a 301/302 redirect with a database behind it. Here is the full request path, from DNS to destination, and what changes when the link is branded.
By ShortFreeURL Team · 28 May 2026
The one-sentence version
A URL shortener stores a mapping between a short path and a long destination, then answers requests for that path with an HTTP redirect. Everything else — analytics, targeting, QR codes — is built on top of that single idea.
What happens when someone clicks
The browser resolves the short domain through DNS to the shortener's edge servers. TLS is negotiated using a certificate issued for that domain. The server takes the path after the slash, looks it up (usually in an in-memory cache before it ever touches a database), and returns a redirect response with a Location header pointing at the destination.
The browser then makes a second request, to the real destination. From the visitor's point of view this is one navigation; two requests happened, and the whole detour typically costs 20–80 milliseconds.
Why the redirect status code matters
A 301 is permanent, so browsers cache it aggressively and may never ask the shortener again. That is fast but it makes changing the destination unreliable for people who already clicked. A 302 is temporary: the browser asks every time, which keeps your click data accurate and lets you change the destination later. Most link platforms default to 302 for exactly that reason.
Where the data comes from
Before returning the redirect, the server records the request: user agent, referrer, IP-derived country and city, language, and any UTM parameters. Bot traffic is classified separately — link previews from WhatsApp, Slack and Facebook all fetch your link before a human ever sees it, and counting those as clicks inflates every report you build.
Generic vs branded links
A generic short link uses the platform's domain. A branded link uses yours — go.yourbrand.com/spring — which means the domain itself is a trust signal. Published click-through studies consistently find branded short links outperform generic ones, and the mechanism is not mysterious: people can see where the link claims to go.
What a shortener is not
It is not a redirect you should chain. Every hop adds latency and a chance of losing referrer data or query parameters. Point the short link directly at the final URL, and let the platform handle targeting rules rather than stacking redirects.