Web API Extension for projectdoc Toolbox is available on the Atlassian Marketplace!
TheThis provides a set of services based on REST to query space properties and document properties.
It's like querying page properties from remote. Just with document properties!

projectdoc Toolbox required!
Please note that the extension requires the commercial projectdoc Toolbox with version 1.12 or later!
projectdoc supports agile teams creating and maintaining project documentation. It provides templates and tools to improve the collaboration of team members.
Representations are rendered in JSON and XML. Queries, supported for projectdoc documents, may also return representations in CSV. Properties for space and document instances are also available in the Java Properties format.