URL Encoder / Decoder

What is URL encoding (percent encoding)?

URL encoding replaces characters that are not allowed or have special meaning in URLs with a % followed by their hexadecimal ASCII value. For example, a space becomes %20, & becomes %26, and = becomes %3D. This ensures URLs can be transmitted safely without ambiguity.

What is the difference between encodeURI and encodeURIComponent?

encodeURI encodes a complete URL and preserves structural characters like : / ? # & = @. encodeURIComponent encodes an individual URL component (like a query parameter value) and escapes all special characters including & = + and ?. Use encodeURIComponent for values you embed inside query strings.

Why does my URL have %20 instead of a space?

%20 is the percent-encoded representation of a space (ASCII 32, hex 0x20). Spaces are not valid in URLs. You may also see + used for spaces in query strings (HTML form encoding), but %20 is the standard URL encoding.

When do I need to URL encode a string?

URL encode whenever you embed user input or dynamic values into a URL — especially query parameters. If a search term is 'hello world & more', it must be encoded as 'hello%20world%20%26%20more' before appending to a URL. Failing to encode can break URL structure or cause parameter injection.

What characters are safe in URLs without encoding?

Unreserved characters safe in all URL positions: A–Z, a–z, 0–9, hyphen (-), underscore (_), period (.), tilde (~). All other characters should be percent-encoded when used in URL components. Structural characters like /, ?, #, &, = are safe in their correct structural positions but must be encoded inside parameter values.

How do I decode a URL with %20 and percent codes in JavaScript?

Use decodeURIComponent('%20') → ' ' for individual components, or decodeURI() for full URLs. In Python: urllib.parse.unquote(encoded_string). In PHP: urldecode($encoded). In Java: URLDecoder.decode(encoded, StandardCharsets.UTF_8).