Electronic data interchange (EDI) is the practice of exchanging business information electronically instead of on paper — for example purchase orders, invoices, and ship notices. EDI is the transfer of structured data, using agreed message standards, from one computer system to another with little or no manual intervention.
Moving from paper, phone, fax, or ad hoc files to electronic exchange typically reduces cost, increases processing speed, cuts transcription errors, and improves relationships with trading partners because both sides operate on the same operational truth.
Procure-to-pay: a concrete example
A common illustration is procure-to-pay: a buying organization procures goods or services from a supplier. The buyer creates a purchase order in its system; the supplier must receive that order in its own system and later issue an invoice. EDI is concerned with how those documents move system-to-system, not how someone retypes them.
Figure A — Manual workflow (offline technologies)
Figure A describes a still-common pattern: the purchase order and invoice journey relies on offline steps — mail, fax, email attachments, spreadsheets, or portal downloads — so a human often bridges the gap between organizations.
Even today, many businesses depend on these offline paths. That raises the cost of integration and can erode operating margins. For a fuller business case, see EDI Benefits.
Figure B — Automated EDI workflow
Figure B shows the same business outcome with EDI: the purchase order is emitted as a standard message from the buyer’s application and consumed directly by the supplier’s application; the invoice follows the same pattern in reverse.
In the automated flow, EDI replaces phone, fax, postal mail, and unstructured email as the primary exchange mechanism. Transactions flow between sender and receiver applications, which supports a manage-by-exception operating model and removes non-value-added manual entry.
EDI standards — which one should I use?
Tens of thousands of standard transaction variants are in use worldwide. Standards emerge by industry, region, and use case. Industry-specific subsets capture data elements a vertical requires.
For example, ANSI ASC X12 is predominant in North America; UN/EDIFACT is widely used in Europe and internationally. HIPAA defines requirements for healthcare transactions in the United States. Common document types — purchase order, invoice, advance ship notice — appear across standards, each with its own version and implementation guide.
Standards specify data formats, segments, and semantics. Trading partners must agree on the same standard version and guideline set for each relationship.
For a deeper tour of syntax, envelopes, and protocols, continue to Standards & Protocols.
Paper PO vs X12 / EDIFACT purchase orders
The diagram below summarizes how a paper purchase order from procurement or ERP relates to equivalent X12 and EDIFACT electronic messages.
