Answer
A practical inventory starts with the transaction sets actually in use, purchase orders, invoices, advance ship notices, functional acknowledgments, and the communication methods each partner requires, whether that is AS2, a VAN, or SFTP. From there, the harder part is documenting how each major partner deviates from the standard: which qualifier codes they use, which segments they populate differently than the spec technically allows, and what their acknowledgment expectations are beyond a basic 997 or 999. Most operational EDI pain comes from these partner-specific quirks, not from the underlying standard itself.
Buyers should ask whether the vendor maintains a library of pre-built maps for common retail, logistics, or manufacturing trading partners, since starting from an existing map that already reflects a partner's known quirks is faster and less error-prone than building every mapping from a blank X12 or EDIFACT template. It is also worth asking how the platform handles a partner who sends a transaction that technically violates the agreed format, since real trading relationships produce malformed data more often than anyone wants to admit, and the software's tolerance for that determines how many after-hours calls the EDI team fields.