Most carriers provide a way to check on the delivery status of a shipment. The ShipEngine Connect platform provides flexibility to adapt to the various approaches carriers use to expose this information.

Single item API

If a carrier provides tracking information via an HTTP API, you should implement the Track function in your app. It will accept various identifiers (like tracking_number) for a single shipment, and your implementation should return the tracking information for that shipment. This Track function will be invoked when a user requests tracking information via a ShipEngine API.

Bulk import

Bulk import requires an app to be built for v4+ of Connect. See Upgrade v2 to v4

If a carrier provides tracking information via a bulk export mechanism, you can implement the ImportTrackingEvents function. It will be invoked on a regular schedule by the ShipEngine platform. By default, a separate call to the function will be made for each connection to your carrier. However, if data for all users is included in a single download, you can specify that the function is only invoked once per scheduled time customizing the scheduled job. When a separate call is made for each connection, the credentials associated with the connection will be passed as input to the function. In most cases, the credentials will include information needed to connect to an FTP server to download files, but the actual implementation can vary depending on what the carrier provides. You may need to add fields to your registration form or settings form to collect additional data from shippers. When you override ScheduledFunction, you have explicit control over what data is sent as input to the ImportTrackingEvents function.

Your function must implement a javascript AsyncGenerator. The function should download the bulk tracking file provided by the carrier, parse it, transform each event from the file into an ImportedTrackingEvent, and yield each individual event via the generator.

Since functions run in an environment with constrained resources (minimal memory and filesystem storage), and tracking files can be large, it is recommended that you process the file and yield events as you stream it from the source. There are javascript stream parsing libraries available for many common formats like CSV, JSON, and XML.

An example TypeScript implementation:

import { ImportTrackingEventsRequest, ImportedTrackingEvent, StandardizedStatusCodes } from "@shipengine/connect-carrier-api";
export async function* ImportTrackingEvents(request: ImportTrackingEventsRequest): AsyncGenerator<ImportedTrackingEvent> {
  // Obtain normalized events, and yield them one at a time
  yield {
    "tracking_info": {
      "tracking_number": "11111",
      "standardized_status_code": StandardizedStatusCodes.Delivered,
  yield {
    "tracking_info": {
      "tracking_number": "22222",
      "carrier_status_code": "AC",
      "standardized_status_code": StandardizedStatusCodes.Accepted,


If you implement both the Track function and ImportTrackingEvents function, the ShipEngine platform will use the Track function to query for updates about each shipment but if a tracking event is imported by ImportTrackingEvents, the Track function will be disabled for that shipment. The platform will expect all future updates to that shipment to come from ImportTrackingEvents.