Welcome to the VonkLoader documentation


VonkLoader is a free, multithreaded tool for Windows / macOS / Linux to upload resources in bulk to any FHIR STU3 server. To install, go to simplifier.net/downloads and log in.


Available parameters are:

    zip file with xml and/or json files with resources, mandatory
    FHIR server base address, mandatory
    load no more than x resources, default is all the resources in the zip
    how many requests are sent in parallel, default is 10
-collectionHandling: AsIs / Split / Transaction
    AsIs: send a collection Bundle as is (to /Bundle)
    Split: send each of the Bundle.resource's from a collection Bundle separately (STU3 only)
    Transaction: convert the collection Bundle to a transaction Bundle and send it to the server base address (STU3 only)
-forcePutInTransaction: resources in collections that have no id get one and are turned into a PUT entry in the transaction.
    By default they are turned into a POST. Only useful in combination with -collectionHandling:Transaction

See also vonkloader --help on running the tool.


vonkloader -file:examples-json-stu3.zip -server:http://localhost:4080

// load Synthea zip
vonkloader -file:examples-json-stu3.zip -server:http://localhost:4080 -collectionHandling:Transaction -forcePutInTransaction

Release notes


  1. Report unknown arguments
  2. Recognize arguments case insensitively


  1. Ignore directory entries, just traverse into them (they were reported as invalid files)
  2. NullReference error could occur on transaction bundles


  1. Add -forcePutInTransaction
  2. Improve log messages
  3. Recognize Batch and Transaction bundles and send them as-is (opposite to Collection bundles that can be transformed to Transaction bundles first).


  1. Exit without user interaction (easier for automation scripts)


  1. First public version, on .NET Core 2.1