The three forms' names on the wire and on disk, and a cheap test of whether a body is worth decoding as one -- DXN.md §6, so every implementation answers the same.
A form is :text (.dxn), :binary (.dxnb) or :schema (.dxns).
identifies?/2 is a prefix test, not a parse: true means "worth
attempting", never "valid". Its text rule mainly tells DXN from JSON in
a body that comes without a type, so it accepts only what JSON cannot
start with: after whitespace, comments and an optional header, a % --
a map, a struct or a schema document. A list or a scalar is DXN too,
but it overlaps with JSON, and stays unrecognised on purpose (Jan,
2026-10-20).
Summary
Functions
The file extension of form, with its dot.
The form media_type names: one of the three, or text for any type with
a structured +dxn suffix (application/vnd.acme.event+dxn). There is
no +dxnb suffix. Media types compare without regard to case; the
caller strips any parameters (; charset=...) first.
Whether body is worth decoding as form.
The media type of form.
Types
Functions
The file extension of form, with its dot.
iex> Dextrin.Format.extension(:schema)
".dxns"The form media_type names: one of the three, or text for any type with
a structured +dxn suffix (application/vnd.acme.event+dxn). There is
no +dxnb suffix. Media types compare without regard to case; the
caller strips any parameters (; charset=...) first.
iex> Dextrin.Format.form("application/vnd.acme.event+dxn")
{:ok, :text}
iex> Dextrin.Format.form("application/json")
:errorWhether body is worth decoding as form.
Binary: the envelope's magic, DX, and a version byte (DXN.md §2.1).
Text and schemas: after whitespace (commas included), # comments and
an optional @dxn "..." header, the first character is %.
iex> Dextrin.Format.identifies?("# config\n%{a: 1}", :text)
true
iex> Dextrin.Format.identifies?("[1 2]", :text)
falseThe media type of form.
iex> Dextrin.Format.media_type(:binary)
"application/vnd.dxnb"