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URL Encoder, Decoder & Parser

Encode and decode text for URLs, see exactly what a link is made of, catch lookalike domains, and tag links for your marketing campaigns.

Encoded

Parse and check a URL

Paste any link to see its parts, decode them, edit the query string, and check whether the address is trying to look like somewhere else.

UTM campaign link builder

Add tracking tags to a link so Google Analytics and similar tools can show which email, post or advert brought each visitor.

Which encoding do I need?

  • One value in a link (a search term, a name, a redirect address): use encodeURIComponent. It encodes &, =, ? and / so they can't break the URL.
  • A whole URL with spaces or accented letters: use encodeURI. It leaves the slashes and question mark alone.
  • Form data and most query strings use + for a space. If a decoded value is full of plus signs, decode it as form data instead.
  • Seeing %2520? That's a space encoded twice (%20, then the % encoded as %25). Decode it twice, then fix whatever encoded it twice.
  • Non-English characters are first turned into UTF-8 bytes, so é becomes %C3%A9 and £ becomes %C2%A3.

Spotting dodgy links

  • The real site is the end of the host name, just before the first / after ://. In https://yourbank.co.uk.example.net/login it's example.net, not your bank.
  • Anything before an @ is a user name, not the site, so https://www.paypal.com@example.net goes to example.net.
  • Some letters in other alphabets look identical to English ones. A domain written with a Cyrillic а can pass for one with a Latin a. Browsers show these as xn-- addresses when they look risky.
  • If in doubt, don't click. Type the address you know into your browser instead.
What should I put in each UTM field?

Source is where the visitor came from (newsletter, linkedin, google). Medium is the type of channel (email, social, cpc for paid search). Campaign names the promotion (autumn-sale-2026). Use term for paid keywords and content to tell apart two links in the same email or advert. Stick to lower case: analytics tools treat Email and email as different values.

Should I add UTM tags to Google Ads?

Usually not. Google Ads adds its own gclid tag automatically when auto-tagging is on, which gives Google Analytics more detail. Use UTM tags for emails, social posts, other ad networks and printed QR codes.

Is anything sent to your server?

No. Encoding, decoding, parsing and the lookalike check all happen in your browser, so it's safe to paste a link you don't trust: nothing is opened unless you click "Open link".

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