URL Encoder & Decoder
Encode special characters for safe use in URLs or decode percent-encoded URL strings back to readable text.
Related Tools
How to Use
- Enter a URL or Text — Paste a URL containing special characters to encode, or paste a percent-encoded string to decode.
- Select Encode or Decode — Choose whether to percent-encode your input for safe URL usage or decode an existing encoded string.
- Copy the Result — Click Encode / Decode, review the output, and copy it for use in your browser, code, or documentation.
About the URL Encoder & Decoder
The WritePadPro URL Encoder and Decoder is an essential web-development utility that converts special characters into their percent-encoded equivalents for safe inclusion in URLs, and reverses the process to restore human-readable text from encoded strings. Proper URL encoding is fundamental to building reliable web applications, constructing API requests, and sharing links that work across every browser and platform.
Why URL Encoding Matters
URLs are governed by RFC 3986, which defines a strict set of characters that are allowed without encoding. Reserved characters — including the question mark, ampersand, equals sign, hash, and forward slash — serve as structural delimiters. If these characters appear as part of a data value (for instance, a search query containing an ampersand), they must be percent-encoded to prevent the browser or server from misinterpreting the URL structure. Failure to encode properly leads to broken links, malformed API requests, and potential security vulnerabilities such as injection attacks.
Query Strings and Form Data
When a user submits an HTML form with the GET method, the browser constructs a query string by encoding each field name and value. Spaces become + signs (per the application/x-www-form-urlencoded specification), and special characters are percent-encoded. Developers building dynamic URLs in JavaScript, Python, PHP, or any server-side language must replicate this encoding. The WritePadPro tool shows the encoded output instantly, helping developers verify their hand-constructed URLs before deploying them.
Internationalized URLs
The modern web serves users in every language, and URLs often contain non-ASCII characters — city names with accents, product titles in Japanese, or blog slugs in Arabic. Browsers display these as readable Internationalized Resource Identifiers (IRIs) but transmit them as standard percent-encoded URIs under the hood. This tool encodes any Unicode text into its proper UTF-8 percent-encoded form, ensuring that internationalized links resolve correctly on every server and in every email client.
API Development and Testing
REST and GraphQL APIs frequently pass parameters through URL query strings. A single unencoded character can break an API call, returning cryptic 400 Bad Request errors. Developers paste query values into this tool to generate correctly encoded parameters, saving debugging time. The decoder is equally valuable: when inspecting server logs or analytics data, encoded URLs are difficult to read. Decoding them reveals the original human-readable values instantly.
Security Considerations
Improper URL encoding is a vector for open-redirect vulnerabilities and parameter-injection attacks. Attackers craft URLs with carefully placed unencoded characters to manipulate server-side logic. Understanding percent-encoding — and verifying that your URLs are properly encoded — is a baseline security practice for every web developer. This tool provides a quick sanity check that complements server-side validation.
Client-Side and Offline-Ready
All encoding and decoding is performed in your browser using standard JavaScript functions. No data is sent to external servers, making the tool safe for use with proprietary API keys, authentication tokens, and internal URLs. The tool remains fully functional offline after the page loads, providing a portable reference for developers working in restricted network environments.
Frequently Asked Questions
What is URL encoding (percent-encoding)?
URL encoding, formally called percent-encoding, replaces unsafe or reserved characters with a percent sign (%) followed by two hexadecimal digits representing the character's byte value. For example, a space becomes %20 and an ampersand becomes %26. This ensures the URL is parsed correctly by browsers and servers.
Which characters need to be encoded in a URL?
Reserved characters that have special meaning in URLs — such as ?, &, =, #, /, and @ — must be encoded when used as data rather than delimiters. Unsafe characters like spaces, angle brackets, curly braces, and pipe symbols should also be encoded. Unreserved characters (A-Z, a-z, 0-9, -, _, ., ~) are safe and do not require encoding.
What is the difference between encodeURI and encodeURIComponent?
In JavaScript, encodeURI encodes a full URI but preserves characters that are part of the URL structure (://?#&=). encodeURIComponent encodes everything except unreserved characters, making it appropriate for encoding individual query parameter values. WritePadPro offers both modes.
Why do spaces sometimes appear as + and sometimes as %20?
In the application/x-www-form-urlencoded format (used by HTML form submissions), spaces are encoded as +. In standard percent-encoding (RFC 3986), spaces are encoded as %20. Both are valid in their respective contexts. The tool supports both conventions.
Can I encode non-English characters in URLs?
Yes. Non-ASCII characters (accented letters, CJK characters, Cyrillic, etc.) are first converted to their UTF-8 byte sequences, and each byte is then percent-encoded. For example, the German umlaut \"u\" becomes %C3%BC. Modern browsers display these as Internationalized Resource Identifiers (IRIs) but transmit them as encoded URIs.