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The MIME Standard

MIME (Multipurpose Internet Mail Extensions) is an Internet standard defined by RFC 1341 that defines how material other than straight ASCII text can be passed in Internet mail messages. It extends the basic message representation protocol (RFC 822) to describe how to represent non-textual material, messages in character sets other than US-ASCII, and other extensions. HTTP uses MIME as the mechanism to describe the content of documents.

Internet mail messages consist of a set of header fields separated from the body of the message by a single empty line. A header field consists of a header field name, such as Date, followed by a colon and the value of the field, for example:

    Date: Mon, 14 Nov 1994 14:04:08 +0100

MIME defines additional header fields to identify the type and subtype of data within the message, the encoding mechanism, content length and other attributes of the message. Recognized content types include text, image, video, audio and application. The subtype specifies the particular format of the data. Messages that conform to the MIME specification must include a MIME-Version header field. MIME header fields might appear as follows:

  MIME-Version: 1.0
  Content-Type: text/html
  Content-Length: 2294

Spinning the Web by Andrew Ford
© 1995 International Thomson Publishing
© 2002 Andrew Ford and Ford & Mason Ltd
Note: this HTML document was generated in December 1994 directly from the LaTeX source files using LaTeX2HTML. It was formatted into our standard page layout using the Template Toolkit. The document is mainly of historical interest as obviously many of the sites mentioned have long since disappeared.