php - Is it ok to have brackets or parenthesis in URL?

Question

Im generating URLs for my AdWord campaigns and some campangin names have brackets in them ( ) and [ ] brackets. And a sample url looks likes this

http://www.website.com/?utm_source=google%5BB%2B%5D&utm_medium=cpc&utm_content=google_ad(B)&utm_campaign=product

Is this fine?

Answer 1

Parentheses “()” may be used as such in the query part of URL (i.e., the part after “?”). It is allowable, but not necessary, to %-encode them, as “%28” and “%29”.

Brackets “[]” shall be %-encoded, as “%5B” and “%5D”, in the query part.

The sample URL, which is a real URL as www.website.com actually exists (please use www.example.com as a dummy domain name, it is guaranteed to not exist), is thus correctly formed.

The general rules for URL syntax are defined in Internet-standard STD 66, which is currently RFC 3986. Its Appendix A specifies the rules for characters, listing parentheses as belonging to the “sub-delims” group which is allowed without %-encoding in the query part but the brackets as belonging to “gen-delims” which shall be %-encoded.