What is URL encoding

URL encoding, also called percent-encoding, replaces characters that have special meaning or are unsafe in a URL with a percent sign followed by two hex digits. The space character becomes %20, the question mark becomes %3F, and so on. Encoding lets data move safely through URLs without breaking the URL structure.

encodeURIComponent vs encodeURI

encodeURIComponent encodes everything that is not a safe character, including reserved URL delimiters such as / : ? = &. Use it when you are encoding a single value such as a query parameter. encodeURI assumes the input is a complete URL and leaves those delimiters alone, encoding only the characters that would break the URL structure. Use it when you have a whole URL with characters that need to be escaped.

Common percent-encoded characters

The table below lists characters that frequently appear percent-encoded in URLs.

URL breakdown and query parameters

When the input is a complete URL, this tool also breaks it into its protocol, host, port, path, and hash, and lists each query parameter in a table. The breakdown uses the browser's built-in URL parser, which follows the WHATWG URL standard.

Common URL tool use cases

URL encoding and parsing come up in many parts of web development.

• Building safe query strings for API calls
• Inspecting tracking and campaign parameters
• Debugging redirect chains and OAuth callbacks
• Decoding shared links that contain encoded values