> For the complete documentation index, see [llms.txt](https://docs.tryterra.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tryterra.co/faq/help-topics/no-data/historical-backfill-returns-nothing/samsung-sdk-no-backfill-or-historical-recovery.md).

# Can Terra backfill historical Samsung Health data?

Samsung Health data comes from the device via Health Connect, not a cloud API, so there is **no server-side endpoint to resend or backfill historical days**.

Data only reaches Terra when the user opens your app and the SDK runs. While the app is closed it sits on the phone. When the app next syncs, the SDK only reaches back a limited lookback window, so days older than that are generally unrecoverable even if the user reopens the app.

The practical recovery path is to **implement a force-sync or pull-to-refresh in your app** and request the missing range via the SDK's getter functions (for example `getDaily`), within that lookback window. See the [mobile SDK docs](https://docs.tryterra.co/health-and-fitness-api/mobile-only-sources) for the getters.