> 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/historical-fetch-size-timeouts-504-413-500.md).

# Why does a historical fetch return a 504 timeout?

Large synchronous [historical pulls](https://docs.tryterra.co/health-and-fitness-api/managing-user-health-data/requesting-historical-data) (`to_webhook=false`) can exceed the response-size limit or the \~30s gateway timeout, returning `504` / `413` / `500`, especially with many activities or `with_samples=true` (heavy GPS/HR series).

What to do:

* **Chunk the request into smaller date ranges** (e.g. several 3-10 day or month-by-month requests) for faster parallel responses, or reduce the range.
* Use `with_samples=false` for summaries.
* Best of all, **use `to_webhook=true`** to return immediately and deliver data asynchronously to your webhook without the size limit.

Within a request, data is returned in chronological order. For latency-sensitive flows, fetch-on-connect and cache, then rely on webhooks. Elevated latency on read endpoints is usually transient infra load, so retry after a short period.

`504`s shown in payload history (versus on your request) mean your server is not acknowledging fast enough, so process payloads asynchronously and return a quick `200`.

{% hint style="info" %}
`end_date` is exclusive, and you cannot request only specific sample types (all or none).
{% endhint %}


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