About URL Encoder
URLs (Uniform Resource Locators) can only contain a very limited set of characters from the US-ASCII charset. These characters include upper and lowercase alphabets (A-Za-z)
, digits (0-9)
, and the special characters (-_~.)
.
Some ASCII characters like ?
, &
, =
, /
have special meaning within URLs. Other ASCII characters like backspace, newline are unprintable. All these ASCII characters and any non-ASCII character must be encoded so that it can be safely placed inside URLs
Which characters are not allowed in URL?
Following class of characters are not allowed within URLs:
Reserved characters: Some characters like : /
?
#
[
]
@
!
$
&
'
(
)
*
+
,
;
=
are reserved for special purpose in the URLs. For example, the character ? is used to specify query parameters, the character & is used to separate two query parameters. These characters cannot be placed in URLs without encoding.
Unprintable characters: ASCII characters in the range 0-31 and 127 are unprintable. These are also called control characters. These characters are not allowed in URLs.
Unsafe characters: Other ASCII characters like space <
>
{
}
|
``` ^
\
are considered unsafe and are not allowed in URLs.
Non-ASCII characters: Any character outside the US-ASCII charset are not allowed in URLs.
What is %20
in a URL?
%20
is the percent encoding of the space
character.
What is %2f
in a URL?
%2f
is the percent encoding of forward slash (/
) character.
What is %3f
in a URL?
%3f
is the percent encoding of question mark (?
)