> 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/webhooks-dedup-and-sync-reliability/track-webhook-request-completion.md).

# How do I know when a data request's last event arrived?

**Webhook payloads include the `terra-reference` header value returned in the synchronous API response**, so you can match deliveries to a specific request and track completion.

Data for a request usually arrives in a **single delivery**. The exception is **Garmin**, which sends data asynchronously in batches that Terra forwards as they arrive.