The complete guide to EDI.

Electronic Data Interchange (EDI) is the silent layer underneath modern B2B commerce. Millions of purchase orders, dispatch advices and invoices flow between trading partners every day — no paper, no manual keying, no waiting for mail.

If your business operates with large retail chains, distributors or supplier networks, EDI isn't a luxury — it's an operational requirement. This guide gives you, in one document, what EDI is, how it evolved, the available implementation options, and how to pick a partner who can take you from zero to production without painful surprises.

REDOK has stood behind this work since 2008 (Megatrend group since 1989) — as a founding member of the EEDIN European EDI network, as the operator of a hub that connects hundreds of companies today, and as the team that integrates ERPs with trading partners across Europe every single day.

What EDI actually means

EDI is the direct exchange of structured business documents between two companies' computers, in an agreed-upon format. No humans retyping numbers from one screen to another. No PDFs being opened, read and manually entered into an ERP.

Three properties must hold for a channel to qualify as EDI:

• Computer-to-computer communication (an emailed PDF doesn't count).
• Structured documents in an agreed format (purchase order, dispatch advice, invoice, catalogue, stock status…).
• A standardised on-the-wire format both sides understand — ANSI ASC X12 (dominant in North America), UN/EDIFACT (dominant in Europe and Asia), or the newer XML/JSON dialects (UBL 2.1, Peppol BIS).

EDI standards you will run into

In practice three "families" cover almost everything you'll encounter:

• UN/EDIFACT — the European standard. Common message types: ORDERS, DESADV (dispatch advice), INVOIC, ORDRSP (order response), DELFOR (forecast).
• UBL 2.1 / Peppol BIS Billing 3.0 — XML formats for e-invoicing in the EU (norm EN 16931). Mandatory for public procurement across the union.
• Proprietary / "flat" formats — CSV, fixed-column, custom XML. Large buyers often impose these on suppliers. A good EDI provider transparently maps these into and out of standard formats to extend reach.

Across two decades of working with companies of every size, the same patterns show up. EDI delivers six measurable benefits — almost every ROI calculation comes back to their sum.

1. Cost savings. Paper, printing, postage, manual data entry and archive storage of traditional documents simply disappear. Typical figure we see: up to 80% lower cost per document versus paper or email flows.
2. Faster processing. Documents land in the ERP in seconds, not days. The order-to-cash cycle typically shortens by several business days.
3. Fewer errors. Eliminating manual rekeying eliminates typos, column swaps and other small but expensive mistakes.
4. Higher efficiency. Your team stops doing "clicky" administrative work and focuses on tasks that actually add value.
5. Stronger partner relationships. EDI is, in practice, a shared language: buyers, suppliers and logistics partners all look at the same data in real time. Fewer "what's the status of my order" calls, more trust.
6. Environmental impact. Less paper, less toner, fewer trucks moving envelopes around. A measurable ESG outcome that is increasingly required in tenders.

EDI isn't new technology. Its roots reach six decades back, which often surprises companies that think of EDI as a "modern IT story".

1960s — American railways

The origins are usually traced to Edward A. Guilbert, a US Army officer who during the Berlin blockade (1948) standardised manifest documents for logistics. He carried those ideas into rail freight in the 1960s, and in 1968 the Transportation Data Coordinating Committee (TDCC) was founded — the first formal body to standardise electronic business messages.

1970s — first industry standards

The TDCC produced the first sectoral formats for transportation; in parallel, the Uniform Communication Standard appeared in retail. Exchange happened mostly over leased telephone lines and early modems.

1980s — ANSI X12 and UN/EDIFACT

ANSI adopted the ASC X12 standard in 1979 — it became dominant in North America. In Europe, UN/EDIFACT (Electronic Data Interchange for Administration, Commerce and Transport) emerged under the UN in 1985 and remains the most widely used European EDI standard to this day.

1990s — the internet arrives

EDI stopped being the privilege of large corporations with their own VANs (Value-Added Networks). The internet drove the cost of exchange down, AS2 emerged (1995), SFTP appeared, and the first web-based EDI platforms came online.

2000s onwards — cloud, mobile, API

Cloud-based EDI services (such as the REDOK network) became affordable for SMEs. Mobile terminals in warehouses generate EDI messages in real time. APIs (REST/JSON) entered the picture as a complementary — not a replacement — channel. EDI is no longer "something only the big players use"; it's infrastructure keeping supply chains running in every EU country.

We're often asked: "Now that APIs exist, isn't EDI obsolete?" Short answer: no. EDI and API are complementary technologies, and most mature systems use them side by side.

EDI's strengths

• Standardisation. UN/EDIFACT, X12, Peppol — every trading partner speaks the same formats.
• Asynchronous batch flow. Perfect for tens of thousands of documents per day. You don't need real-time for the order pipeline.
• Legal grounding. EDI documents carry a clearly defined legal status, digital signatures and audit trails.

API's strengths

• Real-time. When you need to check stock before placing an order, or ping a status in a second.
• Granularity. You can fetch one record, one line.
• Flexibility. JSON / REST is easy to evolve as the business process changes.

The combined approach in practice

A typical modern system uses EDI for the mass document flow (orders, invoices, dispatch advices) and API for real-time queries (stock levels, shipment tracking, invoice status). The REDOK platform supports both flows through one integration point with the ERP.

There are at least eight common ways companies implement EDI. Each has its place — the choice depends on your volume, IT capacity, and the type of partners you exchange with.

Before signing any contract, five questions need a clear answer:

1. Which documents and which partners are in scope? A list of partners, document types (PO, dispatch advice, invoice…) and volumes (documents per week) is the starting point for every ROI calculation.
2. Are the partners ready? Large retail chains in this region (Konzum, Lidl, Plodine, Spar, dm…) require EDI from suppliers and publish clear technical rules. Smaller partners may need a Web EDI portal — that has to be part of the offer.
3. What are your IT capacities? Can your team run mappings and AS2 certificates? Or do you need an outsourced model where the provider holds all of that for you?
4. What is the ROI? Typical framing: (cost of manual handling × number of documents) − (price of the EDI provider). Most companies with more than about 50 documents per week show payback in the first 6–12 months.
5. Who owns the ERP-side integration? The ERP is the most demanding piece. The provider can ship the network and the mappings, but someone has to deliver the ERP connector — usually your ERP partner or internal IT.

From the field: companies that use one EDI provider for all partners have noticeably lower total cost of ownership than those that stitch three or four solutions together. Why:

• Cost-effectiveness. One price, one contract, predictable monthly cost per document. No duplicate licences, no overlap.
• Easy scaling. A new partner is a new configuration in the same platform, not a new project with a new vendor.
• Control and automation. All rules, mappings and flows live in one place. The audit trail is clean.
• Visibility. One dashboard for what's stuck where, who's meeting the SLA, and what statuses partners are at.
• Resilience to change. When a format changes (a new EDIFACT release, a new Peppol spec) — the provider absorbs the change, not you.

REDOK is one of the founding members of EEDIN (European EDI Network) — an alliance of European EDI providers that interconnect their networks. When you send a document through REDOK, it can reach a partner outside Croatia whose local network is another EEDIN member. No duplicate configurations, no "bridges" you maintain on your own.

In practice this means that as a company in Croatia you can use a single REDOK account to exchange documents with partners in Slovenia, Austria, Germany, Hungary and other EU countries — because REDOK and EEDIN partners look like one big network from your side.

Learn more about EEDIN — join the EEDIN LinkedIn group.

Have a concrete case — a buyer asking you for EDI, a new supplier you need to onboard, or an ROI question? Get in touch and we'll come back with a first assessment and a recommendation, with no commitment.