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About This Tool
Web browsers and HTTP servers require specific reserved ASCII and Unicode characters in Uniform Resource Identifiers (URIs) to be represented as percent-encoded octets (`%XX`). This two-way conversion tool uses standard JavaScript `encodeURIComponent` and `decodeURIComponent` to escape query parameters, form payloads, API webhook URLs, and deep links without server latency.
### How Percent-Encoding Works
Under RFC 3986 and WHATWG URL specifications: - **Reserved Characters:** Characters with syntactic meaning in URLs (such as `?`, `=`, `&`, `/`, `:`, `#`, `+`, and spaces) must be escaped when passed as data inside query strings. - **Space Encoding:** Spaces are encoded as `%20` (or `+` in application/x-www-form-urlencoded). - **Unicode Support:** Multi-byte UTF-8 characters (accents, emojis, non-Latin scripts) are transformed into consecutive percent-escaped octets (e.g., `é` becomes `%C3%A9`).
### Worked Encoding & Decoding Example
Converting a complex search query containing spaces, ampersands, and accents: - **Raw Input String:** `https://example.com/search?q=café & lounge + bar` - **Encoded Component:** `https%3A%2F%2Fexample.com%2Fsearch%3Fq%3Dcaf%C3%A9%20%26%20lounge%20%2B%20bar` - **Decoding Mode:** Toggling to "URL Decode" restores all `%XX` hex triplets back into their original human-readable characters.
### Client-Side Processing Note
All URL conversions execute strictly in your local browser runtime via standard Web APIs. No web addresses, authentication keys, or parameter values are transmitted to remote servers.
How to Use
- 1
Paste your raw text or encoded URL string into the input editor.
- 2
Select "URL Encode" to convert reserved characters into %XX hex escapes.
- 3
Select "URL Decode" to transform percent-encoded strings back into readable text.
- 4
Click the copy icon to copy the formatted string directly to your clipboard.
Frequently Asked Questions
What is the difference between encodeURI and encodeURIComponent?
encodeURI preserves protocol delimiters and slashes (://, /, ?, &) intended for whole URLs, whereas encodeURIComponent escapes all delimiters, making it suitable for individual query string key-value parameters.
Why do spaces sometimes appear as %20 and other times as +?
Standard RFC 3986 percent-encoding represents spaces as %20, whereas HTML forms submitted with the application/x-www-form-urlencoded MIME type conventionally encode spaces as + signs.
Are any URLs or API parameters logged or stored by this tool?
No. All encoding and decoding routines operate entirely within your browser memory. No data is stored, tracked, or sent across the network.