X12 envelopes

An X12 file is organized in several nested envelopes, which are pairs composed of header and trailer segments:

  • Interchange envelope (ISA and IEA segments)
    • Sender + Receiver
  • Functional Group envelope (GS and GE segments)
    • Sender + Receiver + Transaction type
  • Transaction Set envelope (ST and SE segments)
    • Transaction type
    • Contains Transaction details

An X12 file can contain several envelopes.

Interchange envelope

The Interchange envelope is composed of ISA and IEA segments. It also contains:

  • Sender identification with ISA ID Qualifier and ISA ID
  • Receiver identification with ISA ID Qualifier and ISA ID
  • Transaction identification with interchange control number

Functional Group envelope

The Functional Group envelope is composed of GS and GE segments. It also contains:

  • Functional Identifier Code (Transaction Type)
  • Sender’s Code
  • Receiver’s Code
  • Group Control Number

Transaction Set envelope

The Transaction Set envelope is composed of the ST and SE segments. It also contains:

  • Transaction Identifier Code (Transaction Type)
  • Transaction Control Number