What are the intended usages of each URI "reserved character"?

Question

We always see reserved characters like /, #, & in URLs; but what are the intended usages of less common ones like @, [, ], ,?

I haven't been able to find a good explanation of what these characters are reserved for.

score 4 · Accepted Answer · edited May 23 '17 at 12:27

@ and :: for HTTP login data for a host (http://john:[email protected])
- : also separates the host from the port (http://example.com:1337)
- note that @ is obviously used in the path of mailto URIs, but allowed in the HTTP URI path, too
[ and ]: for CURIEs ([db:resource/Albert_Einstein])
,: could be used to delimit (query) parameters
;: see this question: What is the semicolon reserved for in URLs?

score 0 · Answer 2 · answered Nov 02 '12 at 18:49

0

@ is for adding username and password to the url, so you could do http://username:[email protected]

answered Nov 02 '12 at 18:49

AlwaysBTryin

Speculation on the rest: precautionary removal of characters they expected this and other protocols to use later, even without a particular use in mind. The RFC says `+`, `,`, and `$` are reserved for query strings, but no use is specified. I've seen brosers that handle these characters without incident. – AlwaysBTryin Nov 02 '12 at 18:51

2 Answers2