postalref

Service Type Identifiers (STIDs)

A Service Type Identifier, or STID, is a three-digit code in the Intelligent Mail barcode that indicates the service type for a mailpiece. It marks the piece as Full-Service or basic, and it sets how USPS handles undeliverable mail and which address correction the mailer gets.

Updated October 28, 202618 sources

What it is

The STID is one field of the Intelligent Mail barcode, or IMb, the barcode on letters and flats. USPS assigns an STID to each combination of services a mailer can request on a mailpiece. Mailers who put the IMb on letters and flats use STIDs, for both basic and Full-Service mail.

Three things decide which STID a piece carries: the address correction services, the mail class, and the service option. The service option is Full-Service or basic. An STID also shows whether the mailer uses Informed Visibility Mail Tracking & Reporting, or IV-MTR.

An STID is not a Service Type Code, the three-digit field in the Intelligent Mail package barcode.

The Postal Intelligent Mail barcode, an IMb that USPS mail processing equipment applies, uses a fixed STID value of 009.

How it works

A mailer picks an STID from the STID Table on PostalPro, by mail class, address correction option, IV-MTR use, and Full-Service or basic IMb. Appendix A, a longer USPS document, describes every available STID. It lays out the choice as a series of steps.

The selection steps in Appendix A.

  1. Find the pages for the mail class, or for Ballot Mail, Political Mail or Miscellaneous.
  2. Decide whether the mailing is basic or Full-Service.
  3. Decide whether to receive IV-MTR scan data.
  4. Decide whether to receive electronic address corrections through ACS.
  5. Choose the ACS record type: OneCode ACS, Full-Service ACS or Traditional ACS.
  6. Choose the disposition for mail that is undeliverable as addressed.
  7. Check whether that disposition needs a printed ancillary service endorsement.
  8. If it does, choose a recommended or an allowable endorsement.
  9. Review the postage and fees tied to the STID and the ancillary service.
  10. Read the Constraints and Notes columns for the line item.
  11. Put the STID from that line item in the IMb.

Reading Appendix A

Appendix A groups its STIDs into five parts.

  • Mail Class: First-Class Mail, Periodicals, USPS Marketing Mail and Bound Printed Matter.
  • Miscellaneous: Priority Mail, Reply Mail and Share Mail.
  • Ballot Mail, for live ballots only.
  • Political Mail, for campaign purposes.
  • Numeric Order, which lists all STIDs.

Within each mail class, the text color shows the address correction notice type.

  • Black: no address correction.
  • Red: manual address correction.
  • Blue: OneCode ACS.
  • Green: Full-Service ACS.
  • Purple: Traditional ACS.

Appendix A was updated on January 21, 2024. That update removed the Change Service Requested Option 1 STIDs for Ballot Mail.

The STID Table

The STID Table is a shorter USPS list, dated January 21, 2024. It leaves out the Secure Destruction STIDs. Promotions and incentive programs may add STIDs for First-Class Mail and USPS Marketing Mail during the year.

The STIDs in the STID Table, by mail class, ACS version, service option and IV-MTR use.

Service Type IDentifier (STID) Table, effective January 21, 2024
STIDMail classGroupOptionService levelInformed Visibility Mail Tracking & Reporting
300First-Class Mail®No Address Corrections – No Printed EndorsementsBasic or NonautomationWithout IV® MTR
310First-Class Mail®No Address Corrections – No Printed EndorsementsBasic or NonautomationWith IV® MTR
260First-Class Mail®No Address Corrections – No Printed EndorsementsFull-ServiceWithout IV® MTR
270First-Class Mail®No Address Corrections – No Printed EndorsementsFull-ServiceWith IV® MTR
700First-Class Mail®Manual Corrections **Basic or NonautomationWithout IV® MTR
040First-Class Mail®Manual Corrections **Basic or NonautomationWith IV® MTR
230First-Class Mail®OneCode ACS®Address Service Requested Opt 1Basic or NonautomationWithout IV® MTR
220First-Class Mail®OneCode ACS®Address Service Requested Opt 1Basic or NonautomationWith IV® MTR
080First-Class Mail®OneCode ACS®Address Service Requested Opt 2Basic or NonautomationWithout IV® MTR
140First-Class Mail®OneCode ACS®Address Service Requested Opt 2Basic or NonautomationWith IV® MTR
504First-Class Mail®OneCode ACS®Change Service Requested Opt 1 ♻Basic or NonautomationWithout IV® MTR
502First-Class Mail®OneCode ACS®Change Service Requested Opt 1 ♻Basic or NonautomationWith IV® MTR
082First-Class Mail®OneCode ACS®Change Service Requested Opt 2 ♻Basic or NonautomationWithout IV® MTR
240First-Class Mail®OneCode ACS®Change Service Requested Opt 2 ♻Basic or NonautomationWith IV® MTR
341First-Class Mail®OneCode ACS®Return Service Requested Opt 2Basic or NonautomationWithout IV® MTR
340First-Class Mail®OneCode ACS®Return Service Requested Opt 2Basic or NonautomationWith IV® MTR
345First-Class Mail®OneCode ACS®Temp-Return Service Requested Opt 2Basic or NonautomationWithout IV® MTR
344First-Class Mail®OneCode ACS®Temp-Return Service Requested Opt 2Basic or NonautomationWith IV® MTR
320First-Class Mail®Full-Service ACS™Address Service Requested Opt 1Full-ServiceWithout IV® MTR
314First-Class Mail®Full-Service ACS™Address Service Requested Opt 1Full-ServiceWith IV® MTR
081First-Class Mail®Full-Service ACS™Address Service Requested Opt 2Full-ServiceWithout IV® MTR
141First-Class Mail®Full-Service ACS™Address Service Requested Opt 2Full-ServiceWith IV® MTR
516First-Class Mail®Full-Service ACS™Change Service Requested Opt 1 ♻Full-ServiceWithout IV® MTR
514First-Class Mail®Full-Service ACS™Change Service Requested Opt 1 ♻Full-ServiceWith IV® MTR
083First-Class Mail®Full-Service ACS™Change Service Requested Opt 2 ♻Full-ServiceWithout IV® MTR
241First-Class Mail®Full-Service ACS™Change Service Requested Opt 2 ♻Full-ServiceWith IV® MTR
343First-Class Mail®Full-Service ACS™Return Service Requested Opt 2Full-ServiceWithout IV® MTR
342First-Class Mail®Full-Service ACS™Return Service Requested Opt 2Full-ServiceWith IV® MTR
232First-Class Mail®Full-Service ACS™Temp-Return Service Requested Opt 2Full-ServiceWithout IV® MTR
222First-Class Mail®Full-Service ACS™Temp-Return Service Requested Opt 2Full-ServiceWith IV® MTR

1 to 30 of 230 codes in the Service Type IDentifier (STID) Table, effective January 21, 2024.

Address correction and ACS

An STID can request Address Change Service, or ACS, a post-mailing service that tells USPS how to handle undeliverable mail. ACS comes in three versions, and each needs its own kind of STID.

Full-Service ACS needs a Full-Service IMb that carries a Full-Service STID. OneCode ACS needs a basic IMb that carries a basic STID. Traditional ACS uses a Participant ID and keyline in the address block, and the STID must request Traditional ACS.

Election and Political Mail

Ballot Mail STIDs are for live ballots only. Other Election Mail uses the First-Class Mail and USPS Marketing Mail pages of the STID Table.

A Ballot Mail STID depends first on the ballot's direction: outbound to the voter, or returned to election officials. USPS strongly recommends First-Class Mail service for all ballots.

Political Mail STIDs are for Political Mail only. They let IV-MTR identify Political Mail during mail processing.

Rules

The allowable encoding range shall be 000–999.

An STID must be a three-digit value from 000 to 999.

Full Service ACS requires a Full Service Intelligent Mail barcode that contains a Full Service STID requesting one of several ancillary services and options.

To get Full-Service ACS, a mailer must use a Full-Service IMb with a Full-Service STID that requests an ancillary service.

OneCode ACS requires a Basic Intelligent Mail barcode that contains a Basic/Nonauto STID requesting one of several ancillary services and options.

To get OneCode ACS, a mailer must use a basic IMb with a basic STID that requests an ancillary service.

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.

A mailer that uses a basic STID requesting ACS must complete the ACS Enrollment Form first. The form sets up the account that delivers and bills the notices.

Mailer ID must be registered for Secure Destruction prior to using this STID.

Before a mailer uses a Secure Destruction STID, its Mailer ID must be registered for Secure Destruction.

Requires the printed text ancillary service endorsement. The option selected must not be printed with the endorsement.

Some STIDs need the printed ancillary service endorsement on the piece. The mailer must print the endorsement without the option number.

Takes effect January 21, 2024

When a printed endorsement is required to receive ACS, as is for USPS Marketing Mail service, “ELECTRONIC SERVICE REQUESTED” must be printed.

When ACS needs a printed endorsement, as it does for USPS Marketing Mail on Ballot Mail, the piece must show ELECTRONIC SERVICE REQUESTED.

Takes effect January 21, 2024

Other items considered Election Mail (e.g., sample ballots, voter registration cards, polling place notifications, etc.) should NOT use these STIDs.

Election Mail that is not a live ballot should not use the Ballot Mail STIDs.

Takes effect January 21, 2024

What goes wrong

An unreadable IMb can change what happens to First-Class Mail. First-Class Mail can be discarded only when an ACS notice can be generated. So if the IMb cannot be read and the piece shows Change Service Requested, USPS may return it as Return Service Requested mail.

On Ballot Mail, the address correction option in the STID overrides a conflicting printed endorsement. The same holds for Political Mail.

Some options charge return postage or a fee for undeliverable mail returned to sender. USPS Marketing Mail pieces pay an added weighted fee for returns.

Some Periodicals STIDs return undeliverable publications at the First-Class Mail single-piece price. USPS warns that these STIDs have a significant financial impact.

When Appendix A and the Domestic Mail Manual disagree, the Domestic Mail Manual takes precedence.

Terms

Service Type IdentifiersSTID, STIDS, STI, Service Type IDs, Service Type ID(s)
A unique three-digit code embedded in the Intelligent Mail® barcode (IMb®) that indicates the service type for an individual mailpiece.
Intelligent Mail BarcodeIMb, 4CB, Intelligent Mail barcode (piece level barcode), 4CB, 4-CB, USPS4CB, USPS 4-State Customer Barcode, 4-state customer barcode
The IMb is a height-modulated barcode that encodes up to 31 digits of mailpiece data into 65 vertical bars using a 4-state symbology.
Service Type CodeSTC
Service Type Codes are designators used to represent USPS classes of mail in conjunction with the type of Extra Service(s) being requested.
Address Change ServiceACS, Address Correction Service
a post-mailing service that provides USPS with instructions on how to handle Undeliverable as Addressed (UAA) mail and provides you with electronic Change of Address (COA) information or the reason for non-delivery
OneCode ACSOCD, OneCode ACS feature
The foundation for today’s Full Service ACS, OneCode ACS allows customers mailing letters or flats to receive electronic or automated address corrections.
Full-Service ACSFS ACS
Based on OneCode ACS® technology, it allows qualified Full Service mailers of letters and flats to receive electronic or automated address corrections.
Traditional ACSTRD
The original version of ACS allows customers mailing letters, flats, or parcels to receive electronic address corrections.
Full-Service Intelligent MailFS, Full-Service, Full-Service Intelligent Mail option
One of two Intelligent Mail offerings that requires a maximum 31-digit Intelligent Mail barcode comprising five fields: the Barcode ID, Service Type Identifier, Mailer ID, Serial Number, and Routing Code. The Full-Service Intelligent Mail option requires unique mailpiece barcodes, the use of Intelligent Mail barcodes on tray labels or container placards, electronic documentation, and the use of Facility Access and Shipment Tracking to schedule appointments for the entry of mailings.
Election MailEM, Official Election Mail
Any item mailed to or from authorized election officials that enables citizens to participate in the voting process — including ballots, voter registration cards, absentee voting applications, and polling place notifications.
Ballot Mail
A type of Election Mail sent to or from an authorized election official containing a live ballot that may be used to cast a vote in an election.
Political Mailpolitical campaign mail
Any material mailed for campaign purposes by a registered political candidate, campaign committee, or committee of a political party, or political message mailing by a political action committee (PAC), super PAC, or other organization engaging in an effort to influence or drive voter mobilization.

Documents

Tech Guides

Publications

Quick Service Guides

Fact Sheets

FAQs

Tools

Applications/Forms

Contacts

For questions about STIDs, USPS lists the phone number 800-522-9085 and the email intelligentmailsupport@usps.gov. For Secure Destruction STIDs, the ACS team takes email at ACS@USPS.GOV and calls at (877) 640-0724, Option 1. IV-MTR customers contact the IV-MTR Help Desk to register Mailer IDs or change the STIDs in their subscription.

Sources