What EDIFACT means
EDIFACT is a grammar for messages rather than a single message. Its syntax rules are published as ISO 9735, which sets out how batch and interactive messages are formatted. Industries then define their own message types on top of that grammar.
For passenger air transport, those message types were agreed by the PADIS (Passenger and Airport Data Interchange Standards) Board and adopted by IATA and Airlines for America members. They cover reservations, ticketing and airport services, and include government data messages such as PNRGOV, which airlines use to send PNR data to border authorities. IATA notes that PADIS version 17.1 is the last it maintains, following the move to its newer Airline Industry Data Model.
In everyday distribution, "EDIFACT" is often shorthand for the traditional GDS model: fares filed through ATPCO, availability from airline inventory and bookings exchanged as compact text messages. NDC replaces this with XML messages in which the airline builds the offer itself.
The shift is gradual. An Accelya report cited by Business Travel News estimated that EDIFACT channels handled about 33% of airline fare distribution in 2023, a share it projected would fall to around 14% by 2028 as NDC grows. Some airlines now charge more for EDIFACT bookings than for NDC ones, which is covered under direct connect.
How EDIFACT works
An EDIFACT interchange is a sequence of short segments wrapped in standard header and trailer segments, separated by special characters.
- Set the delimitersAn optional UNA segment declares the separator characters; if it is absent the defaults apply.
- Open the interchangeThe UNB segment identifies the sender, recipient and interchange reference.
- Start each messageA UNH segment names the message type and version, for example a reservation or PNRGOV message.
- Carry the data in segmentsBusiness data follows in tagged segments, with elements separated by plus signs, components by colons and each segment ended by an apostrophe.
- Close and checkUNT closes each message with a segment count, and UNZ closes the interchange, letting the receiver confirm nothing is missing.
EDIFACT in practice
Message shape (simplified illustration): a government PNR transmission follows the pattern below. Real messages contain many more segments and exact version identifiers.
UNA:+.?*'UNB+...sender...+...recipient...+...date and reference...'UNH+1+PNRGOV:...version...'... data segments for flight and passengers ...UNT+...segment count...+1'UNZ+1+...reference...'
The default separators are the colon for components, the plus sign for data elements, the question mark as a release character and the apostrophe to end a segment. Compared with NDC's XML, this format is compact but hard to read without a specification.
Distribution context: when a travel agent sells a seat on a partner airline in a GDS, the booking request and the airline's confirmation travel between systems as EDIFACT or similar legacy messages, not as web API calls.
Who uses it
Advantages and limitations
Advantages
- It is a mature, widely implemented standard, so nearly every airline and GDS can exchange messages in it.
- The compact format was efficient on the limited networks and computers of earlier decades.
- Standard message types let many companies interoperate without bilateral formats.
Limitations
- It carries limited product detail, which makes it hard for airlines to describe bundles, seats and rich content.
- The format is difficult to read and debug, and fewer developers are familiar with it.
- Some airlines now add surcharges to bookings made through EDIFACT GDS channels, raising costs for agencies that rely on them.
Frequently asked questions about EDIFACT
Is EDIFACT being replaced by NDC?
Gradually. NDC is IATA's XML standard for airline offers and orders, and many airlines are moving sales to it. An Accelya report cited by Business Travel News projected EDIFACT's share of fare distribution falling from about a third in 2023 to around 14% by 2028. EDIFACT is still widely used for interline, codeshare and government messaging.
What is PADIS?
PADIS stands for Passenger and Airport Data Interchange Standards. It is the set of EDIFACT-based message standards agreed by the PADIS Board and adopted by IATA and Airlines for America members for reservations, ticketing and airport services. IATA lists version 17.1 as its final maintained version following the move to the Airline Industry Data Model.
What is the difference between EDIFACT and XML?
Both are ways to structure data for exchange. EDIFACT uses short coded segments separated by characters such as plus signs and apostrophes, and needs a specification to interpret. XML uses named, nested tags that are easier for people and modern tools to read. NDC uses XML, which lets airlines send richer offer content.
Do travel agents need to learn EDIFACT?
Usually not. Agents work with GDS screens, booking tools or portals that translate EDIFACT into readable displays. Developers who build airline integrations, GDS connections or government data feeds are the people who typically work with the raw messages.
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