# FHIR Datastore HAPI FHIR The HAPI FHIR service will be used for two mandatory functionalities: * A validator of FHIR messages * A storage of FHIR message ### A validator Incoming messages from an EMR or Postman bundles are not always well structured and it may be missing required elements or be malformed. HAPI FHIR will use a FHIR IG to validate these messages. It will reject any invalid resources and it will return errors according to the IG. HAPI FHIR is the first check to make sure the data injected in the rest of the system conforms to the requirements. ### A storage Backed by a PostgreSQL database, all the validated incoming messages will be stored. This will allow HAPI FHIR to check for correct links and references between the resources, as well as another storage for backups in case the data is lost. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://jembi.gitbook.io/openhim-platform/packages/fhir-datastore-hapi-fhir.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.