URL Encoder / Decoder

A URL Encoder and Decoder converts text between its raw form and percent-encoded format that can be safely transmitted in URLs. URLs have strict rules about which characters are allowed. Special characters including spaces, ampersands, question marks, and non-ASCII characters must be encoded when they appear as part of a URL parameter value.

URL encoding replaces unsafe characters with a percent sign followed by their two-digit hexadecimal ASCII code. A space becomes twenty percent sign followed by 20. An ampersand becomes percent sign followed by 26. Characters that have special meaning in URLs like question marks, hash symbols, and slashes must also be encoded when they appear in parameter values rather than as URL structural elements.

Web developers use URL encoding when constructing URLs that contain user-generated content or special characters. Search query parameters containing spaces or special characters must be properly encoded to maintain valid URL structure and ensure correct parameter parsing on the receiving end.

API testers use URL encoding when constructing query parameters for API requests. Parameters containing special characters like ampersands that would otherwise be interpreted as parameter separators must be encoded. A parameter value with the text value equals one ampersand value equals two must be encoded so the ampersand does not split the value into two separate parameters.

Digital marketers track URL encoding when building campaign URLs with UTM parameters. UTM parameter values containing spaces, special characters, or non-ASCII text require encoding to ensure proper tracking in analytics platforms. Properly encoded URLs ensure that campaign data is correctly attributed.

The encoder supports standard RFC 3986 percent encoding. All characters except unreserved characters are encoded. The unreserved set includes uppercase and lowercase letters, digits, and the characters hyphen, underscore, period, and tilde. All other characters including spaces, punctuation, and international characters are encoded.

The decoder reverses the process by identifying percent-encoded sequences and converting them back to their original characters. This is useful for examining encoded URLs to understand what parameters are being passed. Decoding a complex tracking URL reveals the actual parameter names and values being transmitted.

Form URL encoding which uses plus signs for spaces is also supported as an option. This encoding variant is used by HTML forms and some API specifications. The options allow toggling between strict RFC 3986 encoding and form-style encoding depending on the requirements of the target system.