Z3 works with FHIR resources. It is especially helpful for Attachment types (opens in a new tab).

Once a file has been uploaded to Z3, the uploaded file URL can be stored in an Attachment's url. A DocumentReference resource has an attachment element inside the content element. Here is an example:

  "resourceType": "DocumentReference",
  "status": "current",
  "content": [
      "attachment": {
        "url": "https://project-api.zapehr.com/v1/z3/object/fruit-vegetables/fruit-and-vegetable-consumption-in-california-residents-2012-2013-.csv",
        "contentType": "text/csv",
        "title": "fruit-and-vegetable-consumption-in-california-residents-2012-2013-.csv"

When you want to download a file from a DocumentReference, take an attachment url and get a presigned URL for it, then download that file using the URL.