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Postal Encyclopedia

Mailer ID

MID

Barcodes & TrackingUpdated 2026-07-24

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

Definition reviewed 2026-07-24. This is a plain-English Plavidian reference; for USPS terms, the Domestic Mail Manual is the authority. For your own job, the final mail class, postage, and preparation are confirmed after list processing and production review.

Related terms in Barcodes & Tracking

Need this applied to a real job?

Ask Plavidian Expert for an answer based on the USPS Domestic Mail Manual, or send us the job and we'll confirm the preparation before you print.

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