Encodeur d'URL

Encode and decode URLs

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À propos de cet outil

URLs are only allowed to contain a limited set of characters, and several of the ones they do allow carry structural meaning. A question mark starts the query string, an ampersand separates parameters, a hash begins the fragment, a slash divides path segments. If a value you are putting into a URL happens to contain one of those characters, the URL breaks - a search for "fish & chips" would end the parameter at the ampersand and treat "chips" as a new one. Percent-encoding solves this by replacing each unsafe character with a % followed by its hex byte value, so a space becomes %20 and an ampersand becomes %26. The receiving end decodes them back. Two things are worth knowing: this is not encryption, since anyone can reverse it instantly, and there are two different encoding scopes - encoding a whole URL versus encoding one value to place inside it - which is the source of most bugs in this area. Everything runs in your browser.

Comment utiliser cet outil

  1. Choose encode or decodeEncode makes text safe to place in a URL; decode turns a percent-encoded string back into readable text.
  2. Paste your inputA single parameter value, a full URL, or an encoded string you want to read.
  3. Read the resultThe output updates as you type, so you can see exactly which characters changed.
  4. Copy itPaste it straight into your request, config or code.

Pourquoi l’utiliser

  • Works both directions, so you can build an encoded URL or read someone else's.
  • Makes it obvious which characters were unsafe, which is often the actual debugging insight.
  • Runs in your browser - URLs containing tokens or personal data are never transmitted.
  • Instant, with no size limit or rate limit.
  • No account required.

Usages courants

  • Building a query string that contains spaces, ampersands or symbols.
  • Reading an encoded redirect URL to see where it actually points.
  • Debugging an API call that fails only when a parameter contains punctuation.
  • Encoding a search term or filename before putting it in a link.
  • Decoding a UTM-laden campaign URL to see the real parameters.

Conseils pour de meilleurs résultats

  • Encode individual parameter VALUES, not the entire URL. Encoding the whole thing turns the structural ? and & into %3F and %26 and breaks it completely.
  • A space becomes %20 in a path and may appear as + in a query string - both are valid in their place, which is why you sometimes see each.
  • Non-ASCII characters encode as multiple bytes: é is %C3%A9 in UTF-8, not a single escape.
  • If a URL already contains % signs, encoding it again produces %25 and double-encodes it. Decode first to check what state it is in.
  • For building campaign URLs specifically, the UTM Builder handles the encoding for you.

Erreurs à éviter

  • Encoding a complete URL rather than the values inside it, which escapes the separators and destroys the structure.
  • Double-encoding by running an already-encoded string through again - %20 becomes %2520.
  • Assuming encoding provides security. It is a formatting rule, not protection; anyone can decode it in one step.
  • Forgetting that + means space in query strings but a literal plus in paths, so a plus sign in an email address needs encoding as %2B.
  • Leaving spaces unencoded and finding that some clients tolerate it while others reject the request outright.

Formats pris en charge

  • URL / query string

Options disponibles

  • Encode
  • Decode

Questions fréquentes

Paste your text above with encode selected. Unsafe characters are replaced with percent-escapes immediately, ready to copy into a URL.

Yes. No account, no limit, and nothing is sent to a server.

Because several characters have structural meaning - ? starts the query, & separates parameters, # begins the fragment. A value containing one of those would be misread as structure, so it is escaped instead.

A space. The percent introduces an escape and 20 is the hex code for the space character. It is the most common escape you will see.

No. It is a formatting convention with no key and no secret - anyone can decode it instantly. It makes characters safe to transmit, not private.

Just the values you are inserting. Encoding a whole URL escapes the ? and & that give it structure, which breaks it - this is the single most common mistake with URL encoding.

Both are used. The + convention comes from HTML form submission and applies within query strings; %20 is correct everywhere including the path. Most servers accept either in a query string.

Encoding an already-encoded string, so %20 becomes %2520 - the % itself gets escaped. It usually appears as a URL that looks almost right but fails, and the fix is to decode once and check before encoding again.

Les gens recherchent aussi

  • url encoder decoder online
  • percent encoding converter
  • what does %20 mean
  • encode url parameters
  • url decode online free
  • html url encoding table
  • double encoded url fix

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