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RFC 2046 - Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types

Published: November 1996
Status: Standards Track
Authors: N. Freed (Innosoft), N. Borenstein (First Virtual)
Obsoletes: RFC 1521, RFC 1522, RFC 1590

Abstract​

STD 11, RFC 822 defines a message representation protocol specifying considerable detail about US-ASCII message headers, and leaves the message content, or message body, as flat US-ASCII text. This set of documents, collectively called the Multipurpose Internet Mail Extensions (MIME), redefines the format of messages to allow for:

  1. Textual message bodies in character sets other than US-ASCII
  2. An extensible set of different formats for non-textual message bodies
  3. Multi-part message bodies
  4. Textual header information in character sets other than US-ASCII

These documents are based on earlier work documented in RFC 934, STD 11 and RFC 1049, but extends and revises them. Because RFC 822 said so little about message bodies, these documents are largely orthogonal to (rather than a revision of) RFC 822.

The initial document in the MIME series, RFC 2045, specifies the various headers used to describe the structure of MIME messages. This second document defines the general structure of the MIME media type system and defines an initial set of media types. The third document, RFC 2047, describes extensions to RFC 822 to allow non-US-ASCII text data in Internet mail header fields. The fourth document, RFC 2048, specifies various IANA registration procedures for MIME-related facilities. The fifth and final document, RFC 2049, describes MIME conformance criteria as well as providing some illustrative examples of MIME message formats, acknowledgments, and references.

Status of this Memo​

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Contents​

Appendices​

MIME Document Series​

  • RFC 2045: MIME Part One - Message Body Format
  • RFC 2046: MIME Part Two - Media Types (This Document)
  • RFC 2047: MIME Part Three - Message Header Extensions
  • RFC 2048: MIME Part Four - Registration Procedures
  • RFC 2049: MIME Part Five - Conformance Criteria and Examples

Primary Media Types​

This document defines the following top-level media types:

Discrete Types​

  • text: Textual data (text/plain, text/html, etc.)
  • image: Image data (image/jpeg, image/png, etc.)
  • audio: Audio data (audio/mpeg, audio/wav, etc.)
  • video: Video data (video/mp4, video/mpeg, etc.)
  • application: Application data (application/pdf, application/json, etc.)

Composite Types​

  • multipart: Multi-part messages (multipart/mixed, multipart/alternative, etc.)
  • message: Encapsulated messages (message/rfc822, message/partial, etc.)
  • Official Text: RFC 2046
  • Official Page: RFC 2046 DataTracker
  • Errata: RFC Editor Errata
  • IANA Media Types Registry: IANA Media Types
  • Obsoletes: RFC 1521, 1522, 1590
  • Related RFCs:
    • RFC 2045 (MIME Message Body Format)
    • RFC 2047 (MIME Header Encoding)
    • RFC 6838 (Media Type Specifications and Registration Procedures)
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