> 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/garmin-unrequested-historical-payloads.md).

# Why did old Garmin payloads arrive without my request?

**This is expected behaviour given Garmin's API design**, not an error on your side.

Why it happens:

* Garmin delivers data asynchronously, with no reference tying it back to the originating request.
* A single end user can be connected to several Terra-powered apps, and Garmin also pushes some historical data automatically (for example, via planned-workout polling).
* If another app requests years of history, Garmin pushes it and Terra must forward it to every connected app. This surfaces as thousands of unrequested or pre-connection-date historical payloads.

**Deduplicate on your side** using summary identifiers and timestamps. See [receiving data updates](https://docs.tryterra.co/health-and-fitness-api/managing-user-health-data/receiving-data-updates) for how payloads arrive.


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