@P, Pioline (Cognizant) Thanks for reaching out. We support transactions when the FHIR service is set to use SQL databases However, due to technical restrictions, transaction type bundles are not supported when the FHIR service is set to use Cosmos DB.
The same way, we only support Transactions with Healthcare Data Services, and we do not support it on Azure API for FHIR.
reference: https://stackoverflow.com/questions/61277127/creating-multiple-bundles-in-azure-api-for-fhir
let me know incase of further queries, I would be happy to assist you.
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