URL Encoder/Decoder
Encode or decode URL strings with percent-encoding.
About the URL Encoder and Decoder
Our free URL encoder and decoder tool converts special characters into their percent-encoded equivalents for safe use in URLs, and decodes percent-encoded strings back to readable text. URL encoding, also known as percent encoding, is essential for constructing valid URLs that contain spaces, special characters, or non-ASCII text. This tool processes all data locally in your browser, ensuring complete privacy for your URL parameters and query strings.
What Is URL Encoding
URL encoding is the process of converting characters into a format that can be safely transmitted within a URL. URLs can only contain a specific set of characters defined by the RFC 3986 standard, which includes uppercase and lowercase letters, digits, hyphens, periods, underscores, and tildes. All other characters must be encoded by replacing them with a percent sign followed by their hexadecimal ASCII value. For example, a space becomes %20, an ampersand becomes %26, and a question mark becomes %3F. This encoding ensures that special characters in data values are not confused with URL structure characters like separators and delimiters.
Why URL Encoding Matters
Proper URL encoding is critical for web applications to function correctly. Without encoding, special characters in query parameters can break URL parsing, cause security vulnerabilities, or lead to incorrect data being sent to servers. For example, if a search query contains an ampersand character, the URL parser might interpret it as a parameter separator rather than part of the search term. URL encoding prevents these ambiguities by ensuring that data characters and structural characters are clearly distinguished from each other.
Common Characters That Require Encoding
Several common characters require URL encoding when used in data values. Spaces are encoded as %20 or sometimes as plus signs in form data. The ampersand (%26), equals sign (%3D), and question mark (%3F) must be encoded when they appear in parameter values to avoid confusion with URL structure. Non-ASCII characters from languages other than English, including accented letters, Chinese characters, Arabic text, and emoji, are first converted to their UTF-8 byte sequences and then each byte is percent-encoded individually.
URL Encoding in Web Development
Web developers encounter URL encoding in many contexts. When building API calls with query parameters, all parameter values should be properly encoded. When constructing redirect URLs, the target URL must be encoded when passed as a parameter. When processing form submissions using the GET method, browsers automatically encode form data in the URL. When working with JavaScript, the encodeURIComponent function handles parameter value encoding, while encodeURI preserves URL structure characters. Understanding when and how to apply encoding correctly is a fundamental skill for web development.
Privacy and Security
All URL encoding and decoding happens entirely in your browser using JavaScript. Your URLs and data are never transmitted to our servers. This is especially important when working with URLs that contain authentication tokens, session identifiers, API keys, or other sensitive parameters. The tool is completely safe for decoding and analyzing any URL regardless of the data it contains.
Frequently Asked Questions
What is the difference between encodeURI and encodeURIComponent?
In JavaScript, encodeURI encodes a complete URI while preserving structural characters like colons, slashes, question marks, and ampersands. encodeURIComponent encodes everything except letters, digits, and a few special characters, making it appropriate for encoding individual parameter values. Our tool uses the component-level encoding approach, which is the safest choice for encoding data values that will be placed into URL parameters.
Should spaces be encoded as %20 or plus signs?
Both representations are valid but used in different contexts. The %20 encoding is used in URL paths and is the standard defined by RFC 3986. The plus sign encoding for spaces is used specifically in application/x-www-form-urlencoded format, which is the default for HTML form submissions. Our tool uses %20 as it is the more universally compatible option.
Can I encode URLs with international characters?
Yes, our tool fully supports international characters including accented letters, Chinese, Japanese, Korean, Arabic, and all other Unicode characters. These characters are first converted to their UTF-8 byte representation, and then each byte is percent-encoded. This process is fully reversible through our decoder.
Is URL encoding the same as HTML encoding?
No, they serve different purposes. URL encoding (percent encoding) makes characters safe for use in URLs, while HTML encoding (entity encoding) makes characters safe for display in HTML documents. For example, the less-than sign is encoded as %3C in URLs but as < in HTML. Using the wrong encoding type can lead to security vulnerabilities like cross-site scripting attacks.
Related Tools
Our other developer tools complement the URL encoder. The Base64 Encoder converts text to Base64 format for data transport. The JSON Formatter validates and beautifies JSON data that is often transmitted via encoded URLs. The Text to Slug generator creates clean URL paths from text strings.
