The data: URI scheme allows you to build URLs that embed small data objects.
data: URIs are supported by most modern browsers - you can read about browser support here.
They are very useful in a couple of specific areas such as embedding graphics and other data items in web pages, CSS files or Greasemonkey scripts. You can read more about data: URIs and see some examples of their use, or use the generator below to create your own. data: URIs are defined in RFC 2397.