Which mode should I use for a query parameter?

Use Component mode. It escapes characters like & and = that would otherwise be read as part of the query string's structure instead of your value.

Why does decoding fail with an error?

Decoding fails when the text contains a % that isn't followed by two valid hexadecimal digits, since that isn't valid percent-encoding. Check for a stray % in the pasted text.

What's the difference from Base64 encoding?

URL encoding (percent-encoding) only escapes characters that aren't safe in a URL, keeping the rest of the text readable. Base64 re-encodes every byte, which is useful for binary data but makes the whole result unreadable as text.

Is my text sent anywhere to encode or decode it?

No. Both operations run locally in your browser using built-in JavaScript functions.

URL Encoder/Decoder & Query String Converter

Encoding

Query string converter

Component mode escapes /, ?, and & too, so it's safe for a single query value.

How to encode and decode URLs

Percent-encode or decode text, a query value, or a full URL, so special characters stay safe wherever the result is used.

Component vs. full URL

"Component" mode escapes every reserved character, including /, ?, and &, which makes it safe to embed as a single value inside a query string or path segment.

"Full URL" mode leaves URL structure characters (: / ? # & = ...) alone and only escapes spaces and other characters that are not valid in a URL, which is the right choice when you're encoding an entire address rather than one piece of it.

Common uses

Building a query string value that contains spaces, &, or =, such as a search term or a redirect URL passed as a parameter.
Reading a URL from a log file or browser address bar that shows %20 and other percent-encoded sequences instead of the original text.
Embedding a file path or non-Latin text (accents, emoji, other scripts) safely inside a link.

How to use it

Choose Component or Full URL depending on whether you're encoding one value or a whole address.
Type or paste text on the left, then choose Encode to fill the right box, or paste an encoded value on the right and choose Decode.
Choose Copy on either side to copy its current content.

Local processing

Encoding and decoding use your browser's own encodeURIComponent, decodeURIComponent, encodeURI, and decodeURI functions. Nothing you type is sent to a ProntoUso server.

URL encoder/decoder FAQ

Which mode should I use for a query parameter?: Use Component mode. It escapes characters like & and = that would otherwise be read as part of the query string's structure instead of your value.
Why does decoding fail with an error?: Decoding fails when the text contains a % that isn't followed by two valid hexadecimal digits, since that isn't valid percent-encoding. Check for a stray % in the pasted text.
What's the difference from Base64 encoding?: URL encoding (percent-encoding) only escapes characters that aren't safe in a URL, keeping the rest of the text readable. Base64 re-encodes every byte, which is useful for binary data but makes the whole result unreadable as text.
Is my text sent anywhere to encode or decode it?: No. Both operations run locally in your browser using built-in JavaScript functions.

Related Tools

Available

URL Encoder/Decoder