Fires once per reopen: an analyst reopened a finalized spread to edit it. The final snapshot it points at is kept and unchanged, but the figures are under revision until the next spread.finalized, so mark your copy stale. The payload carries ids, not figures.
Signature over the exact request body: t=<seconds since the Unix epoch>,v1=<lowercase hex HMAC-SHA256 of "{t}.{body}" keyed with your endpoint's signing secret>. Verify it before trusting the body, and reject a t more than five minutes from your own clock. During a secret rotation both the new and the previous secret verify for 24 hours; each delivery is signed with exactly one.
The event id, identical to the body’s id. Stable across retries and replays, and shared by every endpoint one event fans out to. Delivery is at-least-once, so dedupe on it.
Event id: evt_ plus 24 lowercase hex characters. Also sent as the SpreadSpace-Event-Id header. Stable across retries and replays, so dedupe on it.
Seconds since the Unix epoch at which the event was created server-side. Seconds, not milliseconds. Deliveries are not ordered; reconcile on this.
true for live activity, false for test mode (an ss_test_ key or the sandbox simulator). Branch on it to route test deliveries to a staging handler.
The data object on a spread.reopened delivery, sent once per
reopen: an analyst reopened a finalized spread to edit it. The board is
unlocked and the final snapshot it pointed at is kept unchanged, but
the figures are under revision until the next spread.finalized, so a
receiver holding a copy should mark it stale.
A pointer, not a payload: ids and the version only, no figures and no names.