# Point in time queries

Prevent accidental look ahead

> Section: Guides

> Last updated: **2026-09-26**.

> API version: **v1 (Latest)**. OpenAPI publication: **2026-11-08**.

## Use as_of

Set BELIEFSTATE_TICKER to the requested symbol and BELIEFSTATE_AS_OF to the RFC 3339 cutoff for your question. Set BELIEFSTATE_REQUEST_ID to a new UUID; reuse it only when retrying this exact query.

```bash
curl --fail-with-body \
  --header "Authorization: Bearer $BELIEFSTATE_API_KEY" \
  --header "X-Request-ID: ${BELIEFSTATE_REQUEST_ID:?Set a new UUID for this request; keep it for retries}" \
  "https://beliefstate.ai/v1/beliefs?ticker=${BELIEFSTATE_TICKER:?Set the requested ticker from current coverage}&as_of=${BELIEFSTATE_AS_OF:?Set the requested RFC3339 cutoff}"
```

Future values are clamped.

## Find changed beliefs

GET /v1/beliefs accepts changed_since as an exclusive lower bound for changes and as_of as an inclusive observation cutoff. Use both with a ticker for a historical window.

Reuse the same values on retries. Changing either timestamp creates a different logical request.

## Store the cutoff

Persist the request cutoff with every research artifact and paginated response.

> Do not substitute the time your client downloaded a response for the observation time fields inside the response.

## Agent feedback

Report unclear, stale, or incorrect documentation through [BeliefState support](https://beliefstate.ai/contact). Include this page URL and the smallest reproducible detail.

<!-- BeliefState-Origin: https://beliefstate.ai/docs/guides/point-in-time; Content-Fingerprint: bs-sha256-bd5b9226914b2ba50109415fa9391cfd43fb9febede32d6b6349098cc4c34028 -->