IANA MIME media type registration and file extension tracker

[bact]

This tracker issue is for issues related to the MIME media type registration at IANA, for both SPDX 2 and SPDX 3.

A registered media type, with IANA assignment, is required for content negotiation, and help automation in general (see #1364 for discussion and status of content negotiation).

As of 22 Feb 2026, we have these two media types registered:

Media type name	SPDX version	Format	Extension	IANA assignment
text/spdx	SPDX 2	tag:value	.spdx	https://www.iana.org/assignments/media-types/text/spdx
application/spdx+json	SPDX 2	JSON	.spdx.json	https://www.iana.org/assignments/media-types/application/spdx+json

• SPDX 2 RDF, XML, and YAML formats are not registered.
• SPDX 3 JSON(-LD) format is not registered.
  • We don't have a suggested file extension for SPDX 3 JSON. We may need one for the registration. See Suggested naming convention for SPDX v3 files #987 Suggested file extension for SPDX 3 JSON is .spdx3.json.

[goneall]

Note that we will need this resolved for the SPDX 3 JSON-LD files to be used in the TEI protocol.

[goneall]

From 31 March 2026 Tech Call:

Consensus is .spdx3.json for SPDX 3 file extensions. Media type would application/spdx3+json

General agreement that we would only add new extension / media types on major versions - not minor versions

Bob M. will follow up to confirm the extension type is OK with OMG over the next couple of days

@bact will work with @rnjudge and IANA to request the new media type

[bact]

The request for application/spdx3+json has been submitted to IANA.
The ticket number is 1450117.
See the public-view status at:
https://tools.iana.org/public-view/viewticket/1450117

Update 15 Apr 2026: It is now under "Expert Review". The reviewer is a volunteer designated by the IESG (Internet Engineering Steering Group) rather than an IANA staff, so IANA can't give an estimated time.