What is a good regular expression to match a URL?

javascript

regex

url-validation

javascript-regex

byAlex Kataev·Dec 18, 2024

Here's your go-to regex for URLs:

/https?:\/\/\S+\.\S+/g

This bad boy 🔥 latches onto HTTP/HTTPS links, sidesteps whitespace, and requires a domain and TLD. You're all set to go!

Regex anatomy: a quick walkthrough

Let's dissect the beast:

https?: Matches http, trailing s is optional (supports HTTPS).
:\/\/: Double forward slashes after the colon. No mercy.
\S+: No whitespace needs to apply. Matches one or more non-whitespace characters.
\.\S+: Needs a dot followed by non-whitespace characters (handles TLDs).

Increasing inclusivity: respecting URL diversity

Upgrade the regex to respect variations in URLs:

/(https?:\/\/)?(www\.)?\S+\.\S+/g

Adds www prefix and tolerates missing http://. We believe in diversity. ✊

Accommodating paths and query strings

Some URLs come with extra luggage. Expand your regex's carrying capacity:

/https?:\/\/(?:www\.)?\S+\.\S+(?:\/[^\s]*)?/gi

Now supports paths and query strings. Globe-trotters, assemble! 🌍

When a picture paints a thousand characters

Regex advanced toolkit: handle complex situations

Supporting international URLs & Unicode characters

Here's a multi-lingual regex for the cosmopolitans:

/(?:(?:https?|ftp):\/\/)?[\w/\-?=%.]+\.[\w/\-?=%.]+/gi

Welcomes ftp protocols and charmed by a wide array of Unicode character sets.

Filtering unwanted protocols

Set up a bouncer with negative lookahead:

/https?:\/\/(?!\S*:\/\/)\S+\.\S+/g

Rejects URLs with excess protocols, like cutting a line at the club.

Just domain names, please

Needing a simpler regex for domain names? Here you go:

/((?!-)[A-Za-z0-9-]{1,63}(?<!-)\.)+[A-Za-z]{2,6}/gi

No starting or ending with hyphens. The first and final impression matters.

Real-time validation: letting your users know

document.getElementById('urlInput').addEventListener('keyup', function(e) {
  const whoLetTheDogsOut = urlRegex.test(e.target.value);
  // The feedback. It's alive!
});