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Carriers frequently revise arrival estimates as vessels encounter weather, port congestion, or schedule changes. The shipment.estimated.arrival event fires every time Terminal49 detects an ETA change so you can react immediately.

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Events to subscribe to

EventWhen it fires
shipment.estimated.arrivalETA changes for the port of discharge
container.transport.estimated.arrived_at_inland_destinationETA changes for the inland destination (rail moves)

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What the payload includes

When a shipment.estimated.arrival event fires, the included array contains:
  • An estimated_event object with the new estimated_timestamp
  • The full shipment object with updated pod_eta_at and related fields
  • The tracking_request object so you can match it to your internal reference

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Handle the webhook

Parse the incoming notification, extract the new ETA, and compare it to your stored value: 
app.post("/webhooks/terminal49", (req, res) => {
  const { data, included } = req.body;

  if (data.attributes.event !== "shipment.estimated.arrival") {
    return res.sendStatus(200);
  }

  const shipment = included.find((obj) => obj.type === "shipment");
  const trackingRequest = included.find((obj) => obj.type === "tracking_request");
  const estimatedEvent = included.find((obj) => obj.type === "estimated_event");

  const newEta = estimatedEvent.attributes.estimated_timestamp;
  const bolNumber = shipment.attributes.bill_of_lading_number;
  const portOfDischarge = shipment.attributes.port_of_discharge_name;

  // Compare against your stored ETA
  const previousEta = await getStoredEta(bolNumber);
  const changeInHours = Math.abs(
    (new Date(newEta) - new Date(previousEta)) / (1000 * 60 * 60)
  );

  if (changeInHours > 12) {
    await notifyTeam({
      message: `ETA for ${bolNumber} at ${portOfDischarge} shifted by ${Math.round(changeInHours)} hours`,
      newEta,
      previousEta,
    });
  }

  await updateStoredEta(bolNumber, newEta);

  res.sendStatus(200);
});
ETA events can fire multiple times per day as carriers update their schedules. Filter for significant changes (e.g., more than 12 hours) to avoid alert fatigue.

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Inland destination ETAs

For shipments with an inland rail move, subscribe to container.transport.estimated.arrived_at_inland_destination as well. This event fires when the estimated arrival at the rail ramp or inland depot changes. The payload structure is the same — look for the estimated_event object in included and read the estimated_timestamp field.

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Common patterns

  • Threshold alerts — only notify when the ETA shifts by more than N hours
  • Direction tracking — distinguish delays (ETA moved later) from early arrivals (ETA moved earlier)
  • Customer notifications — forward ETA changes to your customers with a human-readable message
  • Planning updates — adjust warehouse receiving schedules or drayage bookings automatically