Service Type Identifiers (STIDs)

The Intelligent Mail barcode (IMb) is used to identify mailpiece movement through the postal system and support any additional services requested for that mailpiece. The STID defines the mailpiece as full-service or basic (non-automation) and is also used to determine the disposition of undeliverable-as-addressed (UAA) mail and the form of address correction that a mailer desires if any.

Who is STID for?

Mailers using the Intelligent Mail barcodes for letters and flats, both basic (non-automation) and Full-Service.

First Class Mail

First Class Mail



Standard Mail

Standard Mail


The main attributes that determine which STID to use for Intelligent Mail barcoded mail are the address correction services selected for the mailing, the mail class, and the service option. When deciding which STID to use in IMb, mailers need to know:

  • The mail class
  • The address correction service (if any) that is desired
  • The service option – Full-Service or Basic/Nonautomation
  • For Informed Visibility® Mail Tracking & Reporting (IV®-MTR) subscribers, whether IV-MTR is desired
  • The fees, if any, that will be associated with the use of each STID and/or ancillary service request

Mailers that include a Basic Nonautomation STID requesting electronic address corrections (ACS) must complete the ACS™ Enrollment Form to set up an account for fulfillment and billing of OneCode ACS or a SingleSource account for both Full-Service and OneCode ACS notices.

IV-MTR customers interested in receiving the mail piece tracking data must contact the IV-MTR Help Desk to register any new MIDs or add/change any new STIDs in their subscription.

With this information, mailers can reference Appendix A, which has comprehensive information to determine the appropriate STID to use for ancillary services preferred.


Featured Resources

Appendix A: Ancillary Service Type Identifier (STID) Details

Appendix A provides a detailed description of the various address correction options available within basic / Nonautomation and full-service mailings and the STIDs that provide the different undeliverable-as-addressed (UAA) treatments.

Election Mail and Ballot Mail STID Finder

The Election Mail and Ballot Mail Service Type IDentifier (STID) Finder is a tool designed to assist election officials and their mail service providers in selecting an appropriate Election Mail and Ballot Mail STID for their outbound mailings.*

Fact Sheets
Service Type Identifier (STID) Table Effective January 21, 2024

The STID (Service Type Identifier) is a three-digit numeric code used within the Intelligent Mail® barcode (IMb™) on a mailpiece that identifies the address correction or other electronic services desired.

Quick Service Guides
Service Type Identifier (STID) Quick Service Guide

This document provides quick information about the STID (Service Type Identifier) - a three-digit numeric code used within the Intelligent Mail® barcode (IMb™).

Related Products


ACS is a post mailing service that allows mailers to receive change-of-address (COA) and other reasons for non-delivery electronically and reduce the number of manual (hardcopy) address notifications.

Intelligent Mail® Barcode

The Intelligent Mail® barcode (IMb) is used to sort and track letters, cards and flats and offers greater versatility by allowing many services to be requested and embedded within one barcode. The Intelligent Mail barcode combines the data of the existing POSTNET™ and the PLANET Code® barcodes, as well as other data, into a single barcode. 


For questions about Service Type Identifiers (STIDs), please call 800-522-9085 or email us at