• url: URL of an online location where the text of the publication can be found. Cannot be used if title is wikilinked. If applicable, the link may point to the specific page(s) referenced. Remove spurious tracking parameters from URLs, e.g. #ixzz2rBr3aO94 or ?utm_source=google&utm_medium=...&utm_term=...&utm_campaign=.... Do not link to any commercial booksellers, such as Amazon.com. See: WP:PAGELINKS.
  • accessdate: Full date when original URL was accessed; use the same format as other access and archive dates in the citations; requires url. Do not wikilink. Not required for web pages or linked documents that do not change; mainly for use of web pages that change frequently or have no publication date. Can be hidden or styled by registered editors.
  • archiveurl: The URL of an archived copy of a web page, if or in case the url becomes unavailable. Typically used to refer to services like WebCite (see: Wikipedia:Using WebCite) and Internet Archive (see: Wikipedia:Using the Wayback Machine); requires archivedate and url.
    • archivedate: Date when the original URL was archived; preceded by default text "archived from the original on". Use the same format as other access and archive dates in the citations. This does not necessarily have to be the same format that was used for citing publication dates. Do not wikilink.
    • deadurl: When the URL is still live, but pre-emptively archived, then set |deadurl=no. This changes the display order with the title retaining the original link and the archive linked at the end.
  • template doc demo: The archive parameters will be error checked to ensure that all the required parameters are included, or else {{citation error}} is invoked. With errors, main, help and template pages are placed into Category:Articles with incorrect citation syntax. Set |template doc demo=true to disable categorization; mainly used for documentation where the error is demonstrated.
• format: Format of the work referred to by url; for example: PDF, DOC, or XLS; displayed in parentheses after title. HTML is implied and should not be specified. Does not change the external link icon. Note: External link icons do not include alt text; thus, they do not add format information for the visually impaired.

URLs must begin with a supported URI scheme. http:// and https:// will be supported by all browsers; however, ftp://, gopher://, irc://, ircs://, mailto: and news: will require a plug-in or an external application and should normally be avoided. IPv6 host-names are currently not supported.

If URLs in citation template parameters contain certain characters, then they will not display and link correctly. Those characters need to be percent-encoded. For example, a space must be replaced by %20. To encode the URL, replace the following characters with:

sp	"	'	<	>	[	]	|	}
%20	%22	%27	%3c	%3e	%5b	%5d	%7c	%7d

Single apostrophes do not need to be encoded; however, unencoded multiples will be parsed as italic or bold markup. Single curly closing braces also do not need to be encoded; however, an unencoded pair will be parsed as the double closing braces for the template transclusion.