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URL Encoder / Decoder

Percent-encode URLs and query strings, or decode them back to readable text.

Direction

Percent-encode and decode URLs safely

URLs have strict syntax rules, and a handful of characters — spaces, &, ?, #, =, non-ASCII — have special meaning. To include them safely in a URL, they must be percent-encoded. This tool encodes and decodes URLs using the same semantics as JavaScript’s encodeURIComponent / encodeURI / decodeURIComponent / decodeURI.

Which mode should you use?

Component mode (safe for single parameter values):

  • Input: hello world & friends
  • Output: hello%20world%20%26%20friends

Full-URI mode (safe for complete URLs):

  • Input: https://example.com/path with spaces?x=1&y=2
  • Output: https://example.com/path%20with%20spaces?x=1&y=2

Notice that ?, &, =, / and : are left alone in full-URI mode because they are structural.

Common mistakes

  • Double-encoding. Running encode on an already-encoded URL turns %20 into %2520. If your decoder output still looks encoded, decode it a second time — and then ask where the double-encoding originated.
  • Encoding the whole URL with component mode. This breaks the URL by encoding the protocol colon and slashes. Use full-URI mode for complete URLs and component mode only for individual query-parameter values.
  • Not encoding + in form data. If you are targeting a form-encoded endpoint, encode + as %2B.

Frequently asked questions

What is the difference between component and full-URI encoding?
Component encoding (encodeURIComponent) is strict — it escapes every character that has special meaning in a URL, so it is safe for individual query-parameter values. Full-URI encoding (encodeURI) leaves reserved characters like /, ?, #, & alone because they are expected in a complete URL.
Why does decoding sometimes fail?
URLs that were not produced by a percent-encoder can contain bare % signs that are not the start of a valid escape. The decoder throws an error when it hits such a sequence rather than silently returning wrong data.
Should I encode the "+" sign?
The + sign is reserved in the application/x-www-form-urlencoded format, where it means "space". In component mode, + is encoded to %2B to avoid ambiguity.

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