DDH uses the standard OAI-PMH protocol to share the diamond journals with the external world. The DDH protocol implementation supports both Dublin Core and JMEF format. JMEF allows external systems to harvest all of the journal metadata (including the diamond criteria) in DDH.
The DDH OAI-PMH endpoint with the list of supported metadata formats:
https://ddh.diamas.org/oai/journals?verb=ListMetadataFormats
The DDH OAI-PMH endpoint that lists all the journals in JMEF format:
https://ddh.diamas.org/oai/journals?verb=ListRecords&metadataPrefix=oai_jmef
The DDH OAI-PMH endpoint that lists all the journals in DC format:
https://ddh.diamas.org/oai/journals?verb=ListRecords&metadataPrefix=oai_dc