USPS Manifesting – EasyPost Support

USPS manifesting is the process of electronically submitting shipment information to the U.S. Postal Service (USPS). EasyPost automatically manifests USPS shipments each night to ensure compliance with USPS requirements. This process eliminates the need for manual manifesting in most cases.

Some shippers prefer to group shipments together to generate a single Driver Manifest Summary document. Manual manifesting can be performed through EasyPost when this is desired.

Automatic Manifesting

EasyPost automatically manifests all unmanifested USPS shipments each night, typically around 10 PM PST.

Once a shipment has been automatically manifested, it cannot be re-manifested. Attempts to create a manifest after the nightly process may result in an error message stating that a shipment was "not found" or "already manifested."

Note: USPS First Class shipments with predefined_package types Card, Letter, or Flat cannot be manifested. These shipments are non-trackable and will return the error "Unable to create manifest" if included in a manifest request.

Avoiding Auto-Manifesting

The nightly auto-manifest process can be delayed by setting a future shipment date. Two shipment options control this behavior:

shipment.options.label_date: Accepts an ISO date/time stamp that defines the intended shipping date. When not specified, EasyPost defaults to the current UTC timestamp.
shipment.options.date_advance: Increments the label_date by a specified number of days. For example, setting "date_advance": 1 declares that the shipment is scheduled to ship the following day.

Shipments with a future label_date are excluded from the nightly auto-manifest until the declared date is reached.

Example

{
  "options": {
    "label_date": "2025-10-09T10:00:00Z",
    "date_advance": 1
  }
}

Best Practices

Use a future label_date when preparing labels in advance to prevent early manifesting.
Generate ScanForms before 10 PM PST to ensure inclusion in the nightly manifest if same-day processing is required.
Use batches to organize shipments and simplify end-of-day processing.