What Is IATA NDC, and Why Are Airlines Moving to Offers and Orders?
Airline distribution still runs on PNRs, e-tickets and EMDs designed decades ago. A plain-language guide to IATA NDC and ONE Order: what changes, why it is taking so long, and what it means for the engineers building it.
When you buy a flight, a seat and a bag, you probably think of it as one purchase. Behind the scenes, most airlines still store it as three or more separate records, built on ideas from the age of paper tickets. IATA's NDC and ONE Order standards are the industry's attempt to change that. I've spent the last five years working on airline distribution systems, and this is the plain-language guide I would have liked when I started.
How flights are sold today
Traditionally, an airline doesn't really sell to most of its customers directly. It files fares, publishes availability, and lets intermediaries, mainly the global distribution systems (GDSs) used by travel agencies, build what the customer sees. The airline's core system, the PSS (passenger service system), keeps the result in three kinds of records:
- the PNR (passenger name record): who is flying, on which flights, with which requests,
- the e-ticket: the accounting document for the flight itself,
- the EMD (electronic miscellaneous document): the accounting document for extras like seats and bags.
This model is reliable and every part of the industry understands it. But it makes it hard for an airline to sell anything that doesn't fit a fare filed in advance: bundles, personalised prices, rich content like photos of the seat. And keeping three records in sync is a constant source of work and errors.
What NDC changes
NDC (New Distribution Capability) is an IATA program and an XML-based data standard. IATA describes it as a standard that lets sellers interact with airlines through an API to shop, order, pay and service products. It is built around two ideas:
- Offer: the airline itself builds what it wants to sell, for this customer, right now: flights, seats, bags, bundles, prices. The seller asks; the airline answers.
- Order: once the customer accepts an offer, it becomes an order that both sides can retrieve, change and cancel.
In practice this is a set of request/response messages: shopping (AirShopping), pricing an offer (OfferPrice), seats and services (SeatAvailability, ServiceList), creating an order (OrderCreate), and retrieving, changing or cancelling it. The standard is open to any seller, intermediary or IT provider, not only IATA members.
ONE Order: the second half
NDC changes how airlines sell. ONE Order changes how they keep what they sold. IATA describes it as consolidating the PNR, the e-ticket and the EMD into a single, unified record: the Order. One reference number, recognised by everyone who delivers part of the trip, from check-in to the lounge.
Together, IATA calls this Offers and Orders, or modern airline retailing: the airline acting as a retailer instead of a fare filer.
Why is this taking so long?
NDC has been around for more than a decade, and ONE Order is only now moving from pilots to production. According to IATA, leading airlines are starting to move from legacy PSS environments to Offers and Orders architectures, and major carriers are signing contracts or launching order-management programmes. Industry analysts expect most airlines to make the full move in the late 2020s, with widespread adoption probably not before 2030. A few reasons it's slow:
- Everything is connected to the ticket. Revenue accounting, settlement with travel agencies, airport check-in and partner airlines all expect PNRs, tickets and EMDs. Change one and you touch all of them.
- Coexistence is the hard part. No airline switches overnight. For years, systems have to speak both languages and translate between the order world and the ticket world, without losing a booking.
- One standard, many interpretations. NDC has several versions in use, and airlines and sellers implement them differently. Every new connection needs its own testing.
- It's an organisational change. IATA itself calls the move to ONE Order a large-scale transformation that affects internal processes and organisational structure, not just IT.
What it means for engineers
From the inside, the shift feels less like adopting a new API and more like changing the source of truth. A few things I'd keep in mind:
- Model the order first. In the legacy world, the PNR, the ticket and the EMD each hold part of the truth and you reconcile them. In the order world, there is one record, and everything else is derived from it. Designs that start from that idea age better.
- Plan for translation layers. Most of the real work during the transition sits between systems: mapping offers and orders to PNRs and tickets, and back, reliably and at high volume.
- Make every change idempotent and traceable. Orders get changed many times by many channels. Retries, partial failures and "what did the customer actually agree to?" questions are daily business.
- Treat versions and partners as first-class. Schema versions, partner-specific behaviour and certification tests deserve the same care as the core logic.
Why it's worth it
For travellers, the promise is simple: airlines can show and sell what they actually offer, wherever you shop, and change it without three systems arguing. For airlines, it means control over their own product and pricing, and, as IATA notes, a technical foundation for AI-driven distribution. For engineers, it is one of the rare chances to redesign how a whole industry keeps its records. It's slow, and it's worth getting right.