EDIFACT is a standard for tree-based message exchange used in the airline industry; think of it as a third-rate XML designed in the 80s. Airlines are very picky

EDIFACT is a standard for tree-based message exchange used in the airline industry; think of it as a third-rate XML designed in the 80s. Airlines are very picky about using EDIFACT to specify the syntax of messages but usually don't bother to explain the semantics, which is why airline messaging is an n^2 problem. Every airline has custom code for exchanging messages with each of their partner airlines, even though in theory they're all using a well defined messaging standard.