Question 1

What is URL encoding and why is it needed?

Accepted Answer

URLs can only contain a limited set of ASCII characters. Characters with special meaning in URLs (like &, =, ?, #) or characters outside ASCII (like spaces, Unicode) must be percent-encoded. For example, a space becomes %20 and & becomes %26. Without encoding, the browser or server may misinterpret the URL.

Question 2

What is the difference between encodeURI and encodeURIComponent in JavaScript?

Accepted Answer

encodeURI() encodes a full URL but preserves characters that have special meaning in URLs: / : @ ? & = # [ ]. Use it for complete URLs. encodeURIComponent() encodes everything except letters, digits, -, _, ., ~. It encodes /, ?, &, = and is the right choice for encoding individual query parameter values.

Question 3

Why is a space encoded as %20 and sometimes as +?

Accepted Answer

In the URL specification (RFC 3986), a space is encoded as %20. In HTML form encoding (application/x-www-form-urlencoded), spaces are encoded as +. Most modern APIs accept both, but %20 is the universally correct format for URLs. Our tool uses %20 by default.

Question 4

How do I encode a URL with non-English characters?

Accepted Answer

Non-ASCII characters (accented letters, Chinese, Arabic, emoji, etc.) must first be encoded as UTF-8 bytes, then percent-encoded. For example, the é character (U+00E9) becomes the UTF-8 bytes 0xC3 0xA9 which encodes to %C3%A9 in a URL. Modern browsers and our tool handle this automatically.

Question 5

Should I encode the entire URL or just the parameter values?

Accepted Answer

Only encode the individual query parameter values, not the entire URL. Encoding the whole URL would also encode the : // / ? & = delimiters which are structural parts of the URL. For example, encode the value of a search parameter but leave the https:// and domain intact.

Question 6

What is a redirect_uri and why does it need encoding?

Accepted Answer

In OAuth and SSO flows, redirect_uri is a parameter that contains a URL where the user should be redirected after authentication. Since this URL contains : // / ? characters, it must be percent-encoded when passed as a parameter value. For example, https://example.com/callback becomes https%3A%2F%2Fexample.com%2Fcallback.

Character	URL Encoded	Description
Space	%20	Space character in URLs
&	%26	Separates query parameters
=	%3D	Assigns values in query strings
?	%3F	Starts the query string
#	%23	Marks fragment identifier
+	%2B	Plus sign
%	%25	Percent sign itself
/	%2F	Path separator
@	%40	Email addresses or usernames
:	%3A	Protocol separator

Character	Encoded	Usage
Space	%20	Spaces in parameter values
&	%26	Separates query parameters
=	%3D	Assigns values in query strings
+	%2B	Plus sign in parameter data
#	%23	Hash — reserved for fragments
?	%3F	Query string start character

URL Encoder & Decoder

Common URL Encoded Characters

What is URL Encoding?

Common Encoded Characters

Tips & Tricks

Common URL Encoding Use Cases

Frequently Asked Questions

Related Tools