Which characters make a URL invalid?

validation url rfc3986
good picture good · Oct 10, 2009 · Viewed 526.2k times · Source

Which characters make a URL invalid?

Are these valid URLs?

  • example.com/file[/].html
  • http://example.com/file[/].html

Answer

Gumbo picture Gumbo · Oct 10, 2009

In general URIs as defined by RFC 3986 (see Section 2: Characters) may contain any of the following 84 characters: 

ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~:/?#[]@!$&'()*+,;=

Note that this list doesn't state where in the URI these characters may occur.

Any other character needs to be encoded with the percent-encoding (%hh). Each part of the URI has further restrictions about what characters need to be represented by an percent-encoded word.

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