URL Encode/Decode

URL encoding (percent-encoding) converts characters that are not allowed inside a URL — spaces, non-ASCII letters, and reserved punctuation like #, &, and ? — into a safe %XX format. For example, a space becomes %20 and an emoji becomes a multi-byte percent sequence. Without encoding, browsers and servers would misinterpret the URL structure, breaking links, query strings, and form submissions. Encoding guarantees the data travels exactly as intended.

Component scope matches encodeURIComponent/decodeURIComponent: it escapes every reserved character (including /, :, ?, &, =) so the result is safe to embed as a single parameter value. Full URL scope matches encodeURI/decodeURI: it preserves the characters that give a URL its structure (/, :, ?, #, &, =, @) and only escapes characters that are invalid in a complete URL. Use Component scope when encoding a single value; use Full URL scope when encoding a whole URL.

It toggles application/x-www-form-urlencoded convention, used by HTML forms and query strings: encoded spaces are written as + instead of %20. When decoding, a + is converted back to a space. This is the format you see in browser address bars after submitting a form, and it matters when comparing encoded values with server-side tools that use the + convention.

Yes — everything runs 100% locally in your browser. Encoding and decoding are done with plain JavaScript in your tab; nothing is ever sent to a server. The tool also works offline after the page loads. It is safe to encode API keys, tokens, and payloads, though standard security practices still apply elsewhere.

A valid percent escape is a % followed by exactly two hex digits. If a string contains a lone %, an invalid escape like %ZZ, or an incomplete sequence at the end, the decoder keeps it literally instead of throwing an error. Malformed UTF-8 sequences are replaced with the U+FFFD replacement character. This tolerant behavior lets you decode partially-encoded or corrupted input without losing the readable parts.

In Decode mode, when your input contains an = within the query portion (after ?), the tool splits the query string on &, separates each key=value pair, and lists them with the keys highlighted and both parts form-decoded. This makes it easy to inspect or debug URLs with many parameters without reading the raw encoded string.

Both represent a space in query strings, but they come from different conventions: %20 is plain percent-encoding, while + is the application/x-www-form-urlencoded shorthand used by HTML forms. Most servers decode both in query strings, but inside the path component of a URL a literal + is a plus sign, not a space. The Space → + toggle lets you match whichever convention your target system expects.

Yes — completely free, with no registration, no sign-up, no premium tier, and no data collection. Encoding, decoding, and query analysis all run locally on your device. Pair it with our base64 encoder, JSON formatter, and hash generator for a complete developer toolkit.