URL Encoder

Encode and decode URL strings.

Free Online URL Encoder & Decoder

URLs can't contain spaces, ampersands, or unicode characters raw - they need percent-encoding. Dokall encodes strings for safe use in URLs and decodes encoded values back to plain text.

Essential for building query strings, debugging redirect URLs, and handling international characters in web applications.

What is URL Encoding?

URL encoding (also called percent-encoding) converts characters that are not allowed or have special meaning in URLs into a safe format. Each unsafe character is replaced with a percent sign followed by two hexadecimal digits representing the character's ASCII or UTF-8 byte value.

For example, a space becomes %20, an ampersand (&) becomes %26, and a forward slash (/) becomes %2F. The Japanese character becomes %E6%97%A5 (three bytes in UTF-8, each percent-encoded). This ensures that URLs remain valid and unambiguous regardless of what data they carry.

Reserved and Unreserved Characters

URLs have two character categories. Unreserved characters can appear anywhere in a URL without encoding: A-Z, a-z, 0-9, hyphen (-), period (.), underscore (_), and tilde (~). These are always safe.

Reserved characters have special meaning in URL syntax: : / ? # [ ] @ ! $ & ' ( ) * + , ; =. For example, ? starts the query string, & separates query parameters, and # starts the fragment. When these characters are used as data (not as delimiters), they must be percent-encoded.

The tricky part: whether a character needs encoding depends on where it appears. A / in the path component separates directories (do not encode). A / inside a query parameter value is data (encode it). This context-dependent encoding is why there are different encoding functions.

encodeURI vs encodeURIComponent in JavaScript

JavaScript provides two encoding functions with different purposes.

encodeURI() encodes a full URI. It preserves characters that are valid in a URI: : / ? # [ ] @ ! $ & ' ( ) * + , ; =. Use it when you have a complete URL and want to encode only the characters that are never valid in any URL position (spaces, non-ASCII characters, etc.).

encodeURIComponent() encodes a URI component - a piece of a URL like a query parameter value. It encodes all reserved characters including & = ? / because these could conflict with the URL structure. Use it when building query strings: "?search=" + encodeURIComponent(userInput).

Common mistake: using encodeURI() on user input in a query string. If the user input contains &, it will not be encoded, and the browser will interpret it as a parameter separator. Always use encodeURIComponent() for query parameter values.

URL Encoding in Different Languages

In Python: urllib.parse.quote() encodes a string component (like encodeURIComponent). urllib.parse.quote_plus() encodes spaces as + instead of %20 (used in application/x-www-form-urlencoded data). urllib.parse.urlencode() encodes a dictionary into a query string.

In Java: URLEncoder.encode(str, "UTF-8") encodes for form data (spaces become +). For path encoding, use URI class constructors or a library like Apache Commons HttpClient.

In Go: url.QueryEscape() encodes for query strings (spaces become +). url.PathEscape() encodes for path segments (spaces become %20). The net/url package provides URL parsing and construction that handles encoding automatically.

In PHP: urlencode() encodes spaces as + (form encoding). rawurlencode() encodes spaces as %20 (RFC 3986). Use rawurlencode() for path components and urlencode() for form data.

Spaces in URLs: %20 vs + and When Each Applies

There are two ways to encode a space in a URL, and which one is correct depends on the context.

%20 is the standard percent-encoding for a space, defined in RFC 3986. It is correct in all URL components - path segments, query parameter names, query parameter values, and fragments.

+ is an alternative encoding for spaces, but only in the application/x-www-form-urlencoded content type - the format used by HTML form submissions. In this context (and only this context), spaces are encoded as + and + is encoded as %2B.

When building URLs for API calls, use %20. When submitting HTML forms or posting form-encoded data, + is acceptable. Most servers and frameworks handle both, but using the correct encoding avoids edge cases and ambiguity.

Frequently Asked Questions

Why do URLs need encoding?
URLs can only contain a limited set of ASCII characters. Characters like spaces, &, =, ?, and non-ASCII characters (accented letters, CJK characters) have special meanings or are simply not allowed. Encoding converts these characters into a safe percent-encoded format so the URL remains valid and the data is transmitted correctly.
What is the difference between encodeURI and encodeURIComponent?
encodeURI() encodes a full URL, preserving characters that are valid URL delimiters (: / ? # & =). encodeURIComponent() encodes a URL component (like a query parameter value), encoding all special characters including delimiters. Use encodeURIComponent() for user input in query strings. Use encodeURI() only when encoding a complete URL that already has the correct structure.
What does %20 mean in a URL?
The %20 is the percent-encoded representation of a space character. The 20 is the hexadecimal ASCII code for a space (decimal 32). Any character can be represented this way: % followed by its two-digit hex code. For example, %2F is /, %26 is &, %3D is =.
Should I encode the entire URL or just query parameters?
Encode only the parts that contain dynamic or user-supplied data - typically query parameter values and sometimes path segments. Do not encode the URL structure itself (protocol, host, path separators). For example: https://example.com/search?q= + encodeURIComponent(userQuery). Encoding the entire URL with encodeURIComponent would break the protocol and host.
How do I handle Unicode characters in URLs?
Unicode characters are first encoded to UTF-8 bytes, then each byte is percent-encoded. The character (U+65E5) becomes three UTF-8 bytes (0xE6, 0x97, 0xA5), which are encoded as %E6%97%A5. Modern browsers display the Unicode characters in the address bar but send the percent-encoded form to the server. All encoding functions in standard libraries handle this automatically.
What is the difference between + and %20 for spaces?
+ for spaces is only valid in application/x-www-form-urlencoded data (HTML form submissions). %20 is the standard percent-encoding for spaces and is correct everywhere in a URL. When building API URLs, use %20. When submitting form data, + is acceptable. Most servers handle both, but using the correct encoding avoids ambiguity.
Is URL encoding the same as HTML encoding?
No. URL encoding (percent-encoding) converts characters to %XX format for safe use in URLs. HTML encoding converts characters to entity references (&, <, ') for safe display in HTML. They solve different problems: URL encoding ensures URL validity, HTML encoding prevents XSS attacks and display issues. Using one where the other is needed will cause bugs.

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