> 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/data-api-sdk/historical-data-and-backfill/mobile-native-no-backfill-sdk-fetch.md).

# When is historical data available after connect?

[Mobile-native sources](https://docs.tryterra.co/health-and-fitness-api/mobile-only-sources) read from data stored on the user's phone, not a cloud history.

* **Apple Health** does not auto-backfill on connect. The app must call the SDK fetch methods (`getActivity`/`getDaily`/`getBody`/`getSleep`) with a date range, and a completion callback signals when history is pushed.
* **Samsung Health** likewise syncs forward from the link date. To pull older data, use the same SDK date-range methods at connection time, but reach is limited to the recent window Samsung Health still holds on the device, not the full lifetime.
* Each relink starts a fresh connection with a **new Terra user ID**, so older data sits under earlier connection instances.
* **Cloud providers** (Oura, Fitbit, Google Fit, WHOOP, Strava) backfill automatically, usually within an hour or two. Garmin is the exception, with no server-side backfill trigger.

The REST API returns what the device has already pushed, and `end_date` is **exclusive** (use the next day to capture a full day).


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## 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://docs.tryterra.co/faq/help-topics/data-api-sdk/historical-data-and-backfill/mobile-native-no-backfill-sdk-fetch.md?ask=<question>
```

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.