URL Encoder / Decoder
Safely encode special query parameters and URLs into percentage-encoded strings and decode them back.
Understanding Percent-Encoding (URL Encoding)
URL encoding converts characters into a format that can be transmitted safely over the Internet. Characters outside the unreserved ASCII set (such as spaces, ampersands, question marks, and non-English characters) are replaced with a percent sign (%) followed by two hexadecimal digits (RFC 3986).
Frequently Asked Questions
Why do spaces become %20 or + in URLs?
In standard URL percent-encoding (RFC 3986), spaces are represented as %20. In HTML form submission parameters, spaces are sometimes formatted as + signs.
What is the difference between encodeURI and encodeURIComponent in JavaScript?
encodeURI preserves full URL structure delimiters (like :, /, ?, #). encodeURIComponent encodes all special characters including path separators and query delimiters, making it suitable for individual query parameter values.
Is this tool secure for private links?
Yes. All encoding and decoding happen 100% locally in your browser memory.
Why URL Encoding Matters for Web Security
URL encoding ensures that web browsers and HTTP servers parse query parameter key-value pairs accurately. Without proper encoding, characters like &, =, and ? can alter query parameters or introduce HTTP parameter pollution vulnerabilities.