URL Encoder / Decoder

This tool converts text between URL encoding (Encode) and decoding (Decode) formats.

• URL Encode: converts special characters into %XX format for safe transmission in URLs
• URL Decode: converts %XX encoded strings back into readable text
• Useful for URL parameters, API requests, and frontend development scenarios

URL encoding (percent-encoding) is a mechanism used to safely transmit characters in URLs. How it works:

• The input string is first converted into UTF-8 byte sequences
• Each byte is then converted into a hexadecimal value
• Each hex value is prefixed with % to form %XX format

Encoding rules:

• Alphanumeric characters (A–Z, a–z, 0–9) are usually left unchanged
• Spaces are typically encoded as %20 (or + in form submissions)
• Non-ASCII characters (e.g. Chinese, symbols) are encoded into multiple %XX sequences

Example:

• Input: Hello World
• Output: Hello%20World

URL decoding is the reverse process of URL encoding, used to restore encoded strings back to their original form. Decoding rules:

• %XX sequences are decoded back into their original characters
• The + symbol is commonly interpreted as a space in query strings
• To ensure compatibility with form submissions, this tool automatically converts + into spaces during decoding

Example:

• Input: Hello%20World
• Output: Hello World

URL encoding is required to ensure safe and consistent transmission of data in URLs. Reasons:

• URLs are designed to safely support only a limited set of ASCII characters
• Special characters (?, &, =, #) can break URL parsing logic
• Non-ASCII characters (e.g. Chinese, Japanese) cannot be transmitted directly

Therefore, unsafe characters must be converted into %XX format before transmission

The following characters are typically URL encoded:

• Spaces (→ %20 or +)
• Non-ASCII characters (e.g. Chinese, Japanese, Korean)
• Special symbols (?, &, =, #, %, /)
• Control or invisible characters

The following characters are usually NOT encoded:

• English letters (A–Z, a–z)
• Numbers (0–9)
• Safe symbols such as - _ . ~

No.

• All encoding and decoding operations are performed locally in the browser
• No network requests are made
• No user input data is stored or transmitted
• Safe for handling sensitive URLs, tokens, and API parameters