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Postal Encyclopedia

Mailer ID

MID

Barcodes & Tracking

A USPS-issued number used in Intelligent Mail barcodes and electronic documentation to identify the mailer or mail owner.

Definition reviewed 2026-07-24. Plavidian reference, written from the USPS Domestic Mail Manual. Final mail classification, postage, and preparation are confirmed after list processing and production review.

Related terms in Barcodes & Tracking

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