How to use the URL Encoder/Decoder

Paste your string or URL. Pick a mode: `encodeURIComponent` for parameter values (the most common), `encodeURI` for whole URLs (preserves /, ?, &), or `decodeURIComponent` to reverse either. The output updates in real time.

Pourquoi cet outil est important

URLs only allow ASCII letters, digits, and a small set of reserved characters. Spaces, emoji, accented letters, ampersands inside values, and quote marks all need to be percent-encoded. Without encoding, your URL breaks at the first ampersand inside a value, gets truncated at the first space, or 404s on a UTF-8 character. Percent-encoding is the standard fix.

Cas d'utilisation courants

• Building UTM-tagged campaign URLs that contain spaces or accented characters
• Encoding form data for GET requests
• Debugging tracking links where parameters look corrupted
• Constructing API endpoints with user-generated content in the path
• Encoding non-Latin characters (Japanese, Arabic, Cyrillic) for URLs
• Decoding encoded URLs from logs to make them readable

encodeURI vs. encodeURIComponent

`encodeURI` is for whole URLs — it preserves URL structure characters like /, ?, &, # because those are meaningful in a URL. `encodeURIComponent` is for individual values — it encodes EVERYTHING that needs encoding including / and &. Use encodeURIComponent for query parameter values. Use encodeURI for entire URLs you assembled from trusted parts.

Foire aux questions

Why does “+” become “%20” sometimes?
Both can represent a space in a URL — but only in different parts. In query strings, both work. In paths, only %20 works. Encoders consistently use %20 to avoid ambiguity.

Do I need to encode hashtags and ampersands?
In a parameter value: yes (& would otherwise be read as the next parameter). In a URL fragment after #: ampersand is fine. In a URL path: encode hash but leave slashes alone.

Why does my emoji get mangled in URLs?
Emoji are multi-byte UTF-8. Many systems don\u2019t percent-encode them automatically. Always run user-generated content through encodeURIComponent before adding to a URL.

Will encoding break my tracking pixel?
Only if encoded twice. Watch for double-encoding (%2520 instead of %20). Decode once, then encode once.