Track a shipment with the EasyPost Trackers API and receive webhook events

Steps

1. Create a tracker for an existing tracking number (from any carrier) via POST /v2/trackers with body: {tracking_code: 'XXXXX', carrier: 'UPS'} — carrier is optional but improves accuracy.
2. EasyPost immediately returns a Tracker object with the current status, tracking_details array, and est_delivery_date if available.
3. Register a webhook endpoint in your EasyPost account (Dashboard > Webhooks or POST /v2/webhooks with url) to receive tracker.updated events in real time.
4. When EasyPost detects a status change, it POSTs a tracker.updated event payload to your webhook URL; validate the HMAC-SHA256 signature in the X-Hmac-Signature header using your webhook secret before processing.
5. Map EasyPost's status strings (pre_transit, in_transit, out_for_delivery, delivered, available_for_pickup, return_to_sender, failure, unknown) to your internal delivery state machine.