This is a tracking category for CS1 citations that have URI scheme errors.

Help desk

Check |url= value

External links in Citation Style 1 and Citation Style 2 templates are made from two parts: the title (|title=, |chapter=, etc.) and the URL (|url=, |archive-url=, |chapter-url=, |lay-url=, etc.). The |url= parameter and other URL parameters must begin with a supported URI scheme. The URI schemes http://, https:// and the protocol relative scheme // are most commonly used; irc://, ircs://, ftp://, news:, mailto: and gopher:// are also supported.

The URL field is checked to ensure that it contains only Latin characters and does not contain spaces. The URL may be protocol relative (begins with //). If there are no spaces and the URL is not protocol relative, then the scheme must comply with RFC 3986.^[1]

Top- and second-level domain names are checked for proper form. Generally, top-level domain names must be two or more letters; second-level domain names must be two or more letters, digits, or hyphens (first and last character must be a letter or digit). Single-letter second-level domains are supported for:

• all cc TLDs (the country code is not validated)
• the .org TLD
• certain letters of the .com TLD (q, x, z)
• certain letters of the .net TLD (i, q)

Third- and subsequent-level domain names are not checked. The path portion of the URL is not checked.

To resolve this error, ensure that |url= and other URL parameters contain valid URLs. Online tools are available to internationalize URLs that are written in non-Latin scripts:

• "IDN Conversion Tool". Verisign.

Pages with this error are automatically placed in Category:CS1 errors: URL.^[a]

Notes

References