Know what the IMb encodes
An IMb combines identifiers and optional routing information. Understanding the decoded fields is essential when checking mail production or diagnosing incorrect output.
USPS IMb: 3 successful scans/day free; $4.99 one-time unlimited unlock.
Test it with Barcode Inspector.
Point your iPhone at this barcode on your computer screen and scan it. This example is rendered from an actual 65-bar IMb test specimen, not decorative artwork.
Open full-size scannable barcode ↗ if your iPhone has trouble reading the smaller example. Barcode identifier: 00 · Service type: 271 · Mailer ID: 206551 · Serial: 763979467. Get Barcode Inspector on the App Store ↗
Practical barcode knowledge
Barcode identifier
A two-digit field used in the Intelligent Mail barcode data structure.
Service type identifier (STID)
A three-digit value representing the selected postal service configuration. Interpret it using current USPS reference tables.
Mailer identifier (MID)
A six- or nine-digit number identifying a mailer, with the serial-number field length adjusted accordingly.
Serial number
A mailpiece-related number whose size depends on the MID length.
Routing code
An optional routing value that may be absent or contain ZIP, ZIP+4, or delivery-point information.
Decode IMb right from your iPhone.
Read, inspect, copy, and share USPS Intelligent Mail barcode data using Barcode Inspector.
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