Can a payload show its originating source through an aggregator?

It depends on the provider.

It depends on the provider.

• Apple Health: the originating app is identifiable via device_data.name on the activity payload (for example Polar Flow). For daily/body/sleep, contributing sources appear across device_data.name and device_data.other_devices combined. Activity and sleep are keyed by HealthKit/source UUID as summary_id, so different sources never overwrite each other.

• Health Connect (Android): device_data is not currently populated for any data type, so a source coming through Health Connect is indistinguishable.

• Withings: device_data.name reflects the origin of each activity, which may be a connected third-party app (Google Fit, Samsung Health, HealthKit) rather than a physical Withings device, because Withings aggregates connected sources. metadata.upload_type value 6 indicates a third-party origin. Withings Body payloads don't currently carry upload_type or a populated device name.

See the data models reference for the full payload structure.