Markdown Syntax for Object Notation (MSON)
MSON is a plain-text, human and machine readable, description format for describing data structures in common markup formats such as JSON, XML or YAML. The aim of this description format is to facilitate the discussion (and thus validation) of data structures. The format, being agnostic to the common markup formats, is well suited for resource & representations and content negotiation scenarios. In addition, this format also offers (limited) serialization functionality. Similar to the original Markdown to HTML (markup) conversion, MSON enables conversion to other markup formats. This format is being developed by Apiary as a part of the API Blueprint syntax to provide a means for description and validation of HTTP payloads and DRY, media-type agnostic, resource descriptions and to simplify content-negotiation.
I've been developing APIs the past 8 years. First as a Product Manager at API Providers and more recently have been creating API Design, Testing and Collaboration tools at Apiary, the company that came up with both the "API Design" and "API Workflow" concepts!