Webhooks - NowOS

NowOS POSTs every event to the webhook URL you registered, as one envelope:

{
  "id": "evt_01HX…",
  "type": "table.seated",
  "sequence": 4812,
  "createdAt": "2026-06-12T20:05:12Z",
  "data": { … }
}

Verifying the signature

Each delivery carries:

X-NowOS-Event-Id: evt_01HX…
X-NowOS-Event-Type: table.seated
X-NowOS-Signature: t=1781380201,v1=5f8a…

v1 is HMAC-SHA256(webhookSecret, "<t>.<rawBody>") in lowercase hex. Recompute it over the raw body bytes (never a re-serialization) and compare in constant time. Reject timestamps older than ~5 minutes to kill replays.

import { createHmac, timingSafeEqual } from "node:crypto";

function verify(signature: string, rawBody: string, secret: string): boolean {
  const parts = Object.fromEntries(
    signature.split(",").map((p) => p.split("=") as [string, string]),
  );
  if (Math.abs(Date.now() / 1000 - Number(parts.t)) > 300) return false;
  const expected = createHmac("sha256", secret)
    .update(`${parts.t}.${rawBody}`, "utf8")
    .digest("hex");
  return timingSafeEqual(Buffer.from(parts.v1, "hex"), Buffer.from(expected, "hex"));
}

Delivery and ordering

Respond 2xx within 10 seconds to acknowledge. Anything else is retried at 1 m, 5 m, 30 m, 2 h, 12 h, then parked.
Delivery order is not guaranteed (retries interleave). sequence is monotonic per location and order events carry orderVersion — drop anything older than what you already applied. Each event is self-sufficient; you never need the previous one.
id is your idempotency key: the same event re-delivered carries the same id and the exact same body.

Events

Type	Fired when	Notes
`floorplan.published`	the operator publishes the plan	Thin event — re-fetch `GET /floorplan` and re-check your table mapping.
`table.seated`	an order gains tables	`tableIds` is the order’s full current set. `reservationExternalId` is YOUR id when the party came from a reservation; null for walk-ins. Also the confirmation of a seat you initiated.
`order.updated`	a seated order’s items are sent to the kitchen (a Send, or a fired-line void)	Fired total in `totalMinor` — the gross of lines sent to the kitchen, not the live cart. Not emitted on unsent edits or covers changes. Throttled to ≥30 s per order, trailing-edge: the last state always ships.
`check.paid`	a check is paid	One event per check — split bills produce several. `tenders[]` includes `provider_prepaid` consumption; `lines[]` is the itemized summary. `roomCharges[]` names each posting made to a hotel stay (`stayId`, `postingId`, `amountMinor`, tip excluded), `[]` when nothing went to a room. The till posted it: read it, and never post that meal yourself.
`table.freed`	order paid/cancelled, or tables removed	`reason`: `paid`, `cancelled`, or `moved`. A re-seat is `table.freed(moved)` + `table.seated`.
`service.closed`	the last order linked to a reservation closes, with or without a table	`outcome`: `settled` if a payment settled the service, `voided` if everything was cancelled unpaid. `prepaidConsumedMinor` is the total across every check, so its arrival against `check.paid` does not matter. `settled` is terminal for the deposit: the register no longer offers it. After `voided`, a new order may use it.
`reservation.status_changed`	staff marks arrived / no-show / cancelled on the till	Forwarded gestures — update your reservation accordingly.
`reservation.tables_changed`	the floor re-plated a booking from the till	Apply it, then echo the result back with a normal reservation write. `previousTableIds` lets you recognise your own echo and skip it.
`reservation.covers_changed`	the party sat a different number than booked, and staff corrected it on the seated order	Apply it, then echo the result back. Not optional: covers also travel down (booking → order), so a booking left on the old number reinstates it on the till at your next write. `previousCovers` identifies your own echo.
`reservation.note_changed`	staff rewrote the internal note on the seated order	Apply it to the booking’s note, then echo the result back. Same reasoning as covers: the note also travels down (booking → order, where the kitchen ticket prints it), so a booking left on the old text reinstates it at your next write. `note: null` means the note was CLEARED — an edit, not “no change”. `previousNote` identifies your own echo.
`reservation.seat_rejected`	the till refused your seat instruction	The target table got occupied in the race window. Re-seat the party elsewhere; the instruction will not retry until you change the reservation.

Order-derived events fire only for orders with tables — you never see takeaway tickets.