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2. Definition of a Top-Level Media Type

A top-level media type is used to declare the general category of data. The subtype specifies a specific format for that type of data.

Registration Requirements​

The definition of new top-level media types is subject to strict restrictions. New top-level types can only be defined via the IETF standards track process. Any proposal for a new top-level type must be approved by the IESG.

Naming Conventions​

  • Standard top-level types: Registered with IANA
  • Experimental types: Begin with X-
  • Vendor-specific types: Begin with vnd. (as subtypes)

Key Points:

  • Top-level type definition is strictly controlled
  • Requires standards track RFC
  • Subtypes can be defined more freely
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