EDI Resource Center

X12 EDI Standard

X12 is the default U.S. EDI standard. Outside of the U.S., EDIFACT is the X12 equivalent. EDI transactions within the United States must conform to the X12 EDI standard and require compliant, quality software for translation.

In this guide, we'll quickly walk you through the X12 EDI standard, so you can up and running with X12 EDI.

What is X12 EDI?

X12 is formally known as ASC X12 EDI (Accredited Standards Committee X12, Electronic Data Interchange), and is a standard established to govern the use of EDI to electronically exchange information between organizations. X12 EDI includes a set of standards and corresponding messages that define specific business documents widely used across industries today.

Benefits of X12 EDI

The X12 standard allows U.S. companies to communicate information and transfer documents from business-to-business without the hurdles of incompatible software or unsecure connections that leave proprietary data vulnerable to outsiders. X12 has been developed to provide a standardized, data transfer system that creates efficiency in business communications.

As the most common EDI standard in the United States, X12 users represent a vast number of businesses and numerous industries. It's especially prominent in the healthcare industry due to HIPPA (Health Insurance Portability and Accountability Act) regulations enacted in 1996.  The law requires a national standard for electronic health care transactions. Transaction sets for HIPAA EDI are based on X12.

One of the most valuable X12 assets is its comprehensive transaction set which includes commonly used business transactions or documents such as invoices, shipment notices, or purchase orders. X12 boasts over 300 transaction standards within five industry-based subsets, or sub-standards.

X12 EDI Subsets

Due to the prevalent use of X12 across industries, it is considered an umbrella standard with five industry-specific sub-standards or subsets for increased efficiency.

The five functional transaction sets or subsets include:

  • Communications & Controls
  • Finance
  • Transportation
  • Supply Chain
  • Insurance

Each industry uses a specific subset based in the X12 standard. For example, the grocery industry uses subset UCS for its EDI communications and apparel retail uses VICS.

Industry-Specific X12 Subsets:

  • HIPAA - Health Insurance Portability and Accountability Act
  • UCS - Uniform Communication Standard
  • VICS - Voluntary Interindustry Commerce Standards
  • AIAG - Automotive Industry Action Group
  • CIDX - Chemical Industry Data Exchange
  • EIDX - Electronics Industry Data Exchange Group (CompTIA)
  • PIDX - American Petroleum Institute

What X12 Covers

The X12 EDI standard uses a highly specific structure to ensure clear communications across businesses, industries, and national borders. Here, we explore some of its core structural elements.

Syntax Rules to Structure Data

Syntax rules govern the message structure and ensure uniformity regardless of the company, industry, or document.  The result is a data transaction that delivers a clear message to all receivers, regardless of the software platforms used. The standardized structure optimizes files transfers by reducing unnecessary content.

Interactive Exchange Protocol (I-EDI)

The X12 EDI standard uses Interactive Exchange Protocol, which allows companies to exchange business-related messages and documents directly. This dynamic exchange improves communications for both parties, providing shorter response times and removing the problem of delayed responses and inefficient data connections.

Standard Messages for Multi-Country and Multi-Industry Exchange

X12's standardized messaging optimizes data flow not only between businesses but also between industries and countries. Many transaction sets map between X12 and UN/EDIFACT (used internationally), which allows clear communication between the two EDI standards.

Over 300 standardized message types are available through X12.

Common X12 Message Types (Transaction Sets)

  • 204 Motor Carrier Load Tender
  • 276 Claim Status Inquiry
  • 277 Claim Status Response
  • 383 Trading Partner Profile
  • 753 Request for Routing Instructions
  • 754 Routing Instructions
  • 810 Invoice
  • 820 Payment Order/Remittance Advice (EFT)
  • 830 Planning Schedule/Material Release
  • 834 Benefit Enrollment and Maintenance
  • 846 Inventory Inquiry/Advice
  • 848 Material Safety Data Sheet
  • 850 Purchase Order
  • 852 Product Activity Data
  • 855 Purchase Order Acknowledgment
  • 856 Ship Notice/Manifest (ASN)
  • 858 Shipment Information (Bill of Lading)
  • 859 Freight Invoice
  • 861 Receiving Advice
  • 990 Load Tender Response
  • 997 Functional Acknowledgement

Data Element Directories

Data elements are simply the raw data of each transaction, and they function as data fields that comprise the segments within the transaction set. The X12 standard identifies each data element with a reference number as listed in the Data Element Dictionary. In addition, the data element directories for EDIFACT are updated and published every six months by the UNECE (United Nations Economic Commission for Europe). When a U.S. company communicates internationally, these directory updates are crucial for uniformity and for expanding the scope of transaction sets between X12 and UN/EDIFACT.

Guidelines for Electronic Interchange of Structured Data Between Computer Systems

Every standardized system must follow strict guidelines for efficient regulation and uniformity. The current X12 EDI standard is guided by interrelated publications including:

  • Transaction Set Dictionary
  • Segment Dictionary
  • Data Element Dictionary
  • Interchange Control Structures
  • Interconnect Mailbag Control Structures
  • Security Structures
  • Implementation of EDI Structures
  • Application Control Structure
  • ASC X12 Design Rules and Guidelines

Elements that Comprise X12

The X12 EDI standard is characterized by a very specific structure for each of its transaction sets, or documents. While data elements will vary between EDI documents such as purchase orders, invoices, or shipping notices, the general document structure remains the same, promoting uniformity and consistency.

Data Segments

Data segments in X12 are simply categories that organize data, guiding information to the appropriate locations, much like an outline. For example, in the Purchase Order Transaction Set below the required information for the document is outlined and given a unique identifier.


  • ST: Transaction Set Header
  • BEG: Beginning Segment for Purchase Order
  • CUR: Currency
  • REF: Reference Identification
  • PER: Administrative Communications Contract
  • TAX: Tax Reference
  • FOB: F.O.B.-Related Information
  • CTP: Pricing Information
  • PAM: Period Amount
  • CSH: Sales Requirements
  • TC2: Commodity
  • SE: Transaction Set Trailer

Transaction Set Envelope

Once the transaction set (or document) has been built using the necessary data segments and elements, it's ready to be organized for transmission purposes. X12 uses a three-level enveloping system that allows for the careful transfer of multiple transaction sets in one data transfer. The Transaction Set Envelope is the innermost envelope that contains the transfer information for a single transaction set (or single document).

Functional Group Envelope

The middle envelope, or Functional Group Envelope, groups similar types of transaction sets together for a single transmission. Each data transfer may contain several Functional Group Envelopes, each group containing one or more documents of similar type.

Interchange Envelope

The Interchange Envelope is the outer envelope that houses all the Functional Group Envelopes for one data transfer. It's contains data for final transmission and includes information such as:

  • Interchange control numbers
  • Structured mailbox addresses of the sender and receiver
  • Counts of the Functional Groups within the interchange
  • Version of the interchange envelope
  • Time/date stamp

The Interchange Envelope allows for the efficient transfer of multiple, differing documents or messages in one transmission.

X12 Envelope System Enveloping Data Pairs

The beginning and ending of each envelope are defined by data pairs or specific data segments that are assigned for this purpose. Enveloping data pairs provide organization between envelopes, promoting a clear and orderly interchange of data.

Envelope Beginning Ending
Transactional Set ST SE
Functional Group GS GE
Interchange ISA IEA

X12 Background

ANSI established a standards organization known as Accredited Standards Committee X12 (ASC X12) in 1979. They purposed to create and maintain EDI standards and XML schemas. X12 grew in popularity during the late 1980s when most standards body groups in the United States adopted it as their EDI standard. Today, ASC X12 is comprised of 3,000 standard experts who represent over 600 companies across diverse industries. X12 remains the most widely used EDI standard in the U.S.

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