URL Encoder/Decoder — Frequently Asked Questions

It replaces characters that have special meaning in URLs (like &, =, ?, #, space) with their percent-encoded equivalents (%26, %3D, %3F, %23, %20) so they can be safely passed in URL paths or query strings.

Encode a component when you are embedding user input or a value into a query string. Encode a full URL when you have a complete URL with structure (scheme, host, path) that needs to survive being passed as a string.

Decoding fails if the input has invalid escape sequences — like a % followed by characters that are not valid hex digits. Common cause: double-encoded URLs or copy-paste artifacts.

+ for spaces is specific to application/x-www-form-urlencoded form bodies and query strings. %20 works everywhere including URL paths. We always use %20 to avoid ambiguity.

No. Encoding and decoding happen entirely in your browser using JavaScript built-in encodeURIComponent / decodeURIComponent. Nothing leaves your device.