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Comment by xcskier56 | Hacker News Reader

Very cool and impressive work! One question I have is how you think about handling custom data fields. FHIR has the `extension` attribute on all DomainResources that allows you to store any non-standard information, but building code and value sets to properly map this data can be cumbersome and time-consuming.

Do you have any happier/easier paths for extending the core data model to handle custom data?

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Good question. Custom data is tricky. The first thing we always try to do is dig deep into the FHIR spec to see if the data is truly custom, or if there is an existing FHIR representation that will actually work. In many cases, there are good options, and it's nice to work within the spec.

If not, then falling back to extensions is the next logical step. FHIR extensions can be clunky to work with. Our client libraries provide a bunch of helper utilities to make it easier.

In extreme cases, we have created custom FHIR resources via custom StructureDefinition and SearchParameter resources to represent completely unique data elements (examples: https://github.com/medplum/medplum/blob/main/packages/defini...).

Thanks for the thoughts! I agree that FHIR extensions are clunky and very commonly the data you're trying to store can be represented by a FHIR resource. Extensions are clunky, but for some of our projects have been the only way to store a couple pieces of data that we need.

Your use of custom StructureDefinitions for the very non-FHIR models that you need is impressive. I don't think I've seen such a clear example out there of someone extending FHIR to this degree. Well done!

Thanks. You might be the first person outside of the Medplum team to look at that file, happy to hear a positive review.

Another question that I can't quite figure out from your docs is if your bots functionality works with non-AWS hosting?

At present, Bots are AWS-only. We have an active enterprise customer who is exploring porting Bots to Google Cloud Functions. Azure Functions are on the longer term roadmap too.

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