🔗 URL Encoder/Decoder
Encode or decode URLs for safe transmission
About URL Encoder/Decoder
The URL Encoder & Decoder is a specialized development tool designed to convert text strings into percent-encoded strings (URL encoding) and vice versa. URLs (Uniform Resource Locators) are designed to identify resources on the web, but they are restricted to a very small subset of characters from the US-ASCII character set. Characters that are not in this allowed set must be formatted before they can be sent over the internet. This process is called URL encoding, or percent-encoding. The tool converts invalid or reserved characters into a % symbol followed by a two-digit hexadecimal representation of the character's UTF-8 byte value.
There are two primary reasons why URL encoding is necessary: syntax protection and character compatibility. First, certain characters have predefined, structural meanings in a URL. For example, the slash (/) separates path segments, the question mark (?) initiates a query string, the ampersand (&) separates query parameters, and the equal sign (=) matches a parameter name to its value. If you need to include these characters as actual data inside a parameter (such as passing a redirect URL or an email address in a query string), they must be encoded. If they are left unencoded, the browser will interpret them as part of the URL's structure, leading to broken routing, truncated query parameters, or server errors.
Second, URLs cannot natively contain spaces or characters from international alphabets (such as Cyrillic, Chinese, or Arabic characters) or emojis. To send these characters safely, they must be converted into their raw bytes and encoded. The URL Encoder & Decoder handles these conversions instantly. Operating entirely inside your web browser, this utility ensures that your raw links, database queries, and API parameters are encoded safely and privately without sending any data to external servers.
Key Features
✨ Bidirectional Conversion Engine
Supports both URL encoding (converting plain text, parameters, or full links to percent-encoded format) and URL decoding (translating percent-encoded strings back to standard text).
✨ RFC 3986 Standard Compliance
Encodes characters in accordance with the RFC 3986 specifications for Uniform Resource Identifiers (URIs), ensuring compatibility across all modern web servers and browsers.
✨ Flexible Space Formatting
Allows users to toggle between standard path-safe encoding (which represents spaces as %20) and application query-safe encoding (which represents spaces as a plus sign +).
✨ Local Browser-Based Parsing
Processes your URLs locally on your device using JavaScript. This keeps your URLs, API keys, tokens, and redirect parameters private and secure.
How to Use URL Encoder/Decoder
Input Your Target Text or URL
Paste your raw string, URL parameters, or encoded link into the input editor pane.
Select Encoding Settings
Choose whether you want to encode the string (converting special characters) or decode the string (restoring percent-encoded characters).
Choose Space Handling Format
Decide whether to encode spaces as "%20" (standard for paths and JSON) or "+" (standard for HTML form data queries).
Copy the Output Link
Click the "Copy" button to save the converted string to your clipboard, and paste it directly into your application code or web browser.
To use the URL Encoder & Decoder, enter your text in the input box. The tool is designed to parse raw URLs, complex query strings, and standard text blocks. Once your text is loaded, select your desired action. If you are preparing a URL query parameter, click "Encode." If you have an API response or log file with encoded characters (like %20 or %3F) and want to read it, click "Decode." The tool updates the output field instantly.
A common scenario that requires URL encoding is passing a redirect URL as a parameter inside another URL. For example, if you want to redirect a user back to https://example.com/dashboard?user=active&session=new after they log in, you might construct a URL like: https://login.com/?return=https://example.com/dashboard?user=active&session=new. However, this URL contains multiple question marks and ampersands. The browser will assume session=new is a parameter for login.com instead of the redirect URL. To resolve this, you must run the redirect URL through the encoder, producing: https://login.com/?return=https%3A%2F%2Fexample.com%2Fdashboard%3Fuser%3Dactive%26session%3Dnew. Now, the login server can extract the parameter cleanly and redirect the user without error.
Handling Double Encoding: Be careful not to run already-encoded text through the encoder a second time. If you encode a string containing %20 again, the percent symbol (%) will be encoded to %25, producing %2520. When decoded, this will only return %20 instead of the original space. If you see %25 patterns in your URLs, it is a sign of double-encoding, which can be resolved by running the string through the decoder twice.
Benefits of Using Our Tool
Prevents Broken Redirections
Ensures that redirect links, deep links, and affiliate parameters are formatted correctly, preventing web servers from throwing 400 Bad Request errors.
Optimizes Database Parameters
Safely formats search terms, user input, emails, and path strings for use in HTTP queries, keeping data streams clean and error-free.
Maintains High Data Security
Performs all operations client-side, preventing API tokens, session keys, and database queries from being logged by external servers.
Technical Deep-Dive: RFC 3986 URI Specifications and JavaScript URL Methods
The standard governing URL syntax is RFC 3986, which defines how Uniform Resource Identifiers (URIs) are structured. Under this standard, any character that is not part of the unreserved set must be percent-encoded when used in specific URI components. The unreserved set is defined strictly as:
unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~"To implement URL encoding in web applications, JavaScript provides two native global functions: encodeURI() and encodeURIComponent(). Understanding the difference between these two functions is critical for web developers. The encodeURI() function is designed to encode a complete, functional URL. It does not encode characters that are essential to the URL's structure, such as http://, /, ?, &, =, and #. Conversely, encodeURIComponent() is designed to encode a single segment of a URL, such as a query parameter value. It encodes every character except the unreserved set, converting slashes, colons, question marks, and ampersands into their hexadecimal equivalents.
Let's compare how they handle the same string:
const string = "https://example.com/?user=john&role=admin";
console.log(encodeURI(string));
// Output: https://example.com/?user=john&role=admin (unchanged)
console.log(encodeURIComponent(string));
// Output: https%3A%2F%2Fexample.com%2F%3Fuser%3Djohn%26role%3DadminIf you use encodeURI() on a query parameter value that contains an ampersand, the parameter will break the query string structure because the ampersand will remain unencoded. Therefore, developers must use encodeURIComponent() for parameter values and encodeURI() only when validating an entire URL string.
In PHP, URL encoding is handled by two sets of functions. The legacy urlencode() and urldecode() functions implement the application/x-www-form-urlencoded format, which encodes spaces as +. The newer, RFC 3986-compliant rawurlencode() and rawurldecode() functions encode spaces as %20. For modern APIs, rawurlencode() is highly recommended to prevent routing issues with clients that expect strict RFC 3986 encoding.
From a security perspective, input validation should always be executed after URL decoding. If you validate input while it is still percent-encoded, malicious scripts (such as Cross-Site Scripting payloads or SQL injection syntax) can easily bypass filters, only to be executed when the database or backend framework decodes the string later in the processing loop.