What characters must URL encoded?

The URL should also include a list of characters that are not permitted.

ASCII control characters (e.g. {backspace, vertical tab, horizontal tab, line feed etc), unsafe characters like space , , < , > , , etc, and any character outside the ASCII charset is not allowed to be placed directly within URLs.|Backspace, vertical tab and horizontal tab etc., unsafe characters such as space.,, >.,,, etc. characters that are not within the ASCII character set are not allowed be placed directly in URLs.} There are also characters with special meanings within URLs.

What is URL encoded? URL encoding refers to the process of translating URL characters into unprintable characters, or characters with special meanings within URLs, in order to create a representation that's unambiguous and accepted by all web browsers and servers. These characters include an ASCII control character, a Uniprintable character commonly used for output control.

You might also wonder, "What are reserved characters in URL?"

These characters have special meanings and are called reserved characters. Forward slash characters can be used to separate parts of a URL or, more generally, a URI. These meanings are not available for unreserved characters.

What is %2f?

URL Encoding converts characters to a format that can easily be transmitted over the Internet. - w3Schools. This means that "/" can be used as a separator, but "%2f", which is an ordinary character, simply replaces the "/" character in your url.