Chapter 6 EDI vs. API: The Real Differences and When to Use Each

What is the difference between EDI and API?

EDI moves standardized documents. An API moves requests and responses against a specific system.

The practical consequence: with EDI you can learn the standard once and apply most of it across many partners. With APIs you learn each one separately. That trade-off runs in both directions, which is why neither technology has replaced the other.

Is EDI batch and are APIs real time?

Not reliably. This is the most repeated claim in the comparison and the least useful one.

EDI files are often exchanged on a schedule, and APIs are often called on demand, but both patterns exist in both technologies. An API can queue work asynchronously and take minutes to respond. An EDI connection can be polled frequently enough that the difference stops mattering operationally. Our own guidance for inventory and orders is hourly transmission with daily as the minimum.

Ask about frequency and latency directly instead of inferring them from the technology. A supplier who refreshes an inventory API once a day is slower than a supplier sending an EDI file every hour.

When should you use EDI?

Use EDI when a trading partner requires it, which is the case that decides most of these conversations.

If a distributor or retail partner hands you an implementation guide specifying document types, a standard version, identifiers, and a communication method, choosing an API instead is not an option you have. Their requirement is contractual.

EDI also fits well when you exchange the same document types repeatedly with several partners at once. The shared standard means a second supplier's purchase order flow resembles the first one, even though the specifics differ. That similarity is worth a lot when your partner count is growing.

Where EDI costs you: setup time, certification with some partners, and specification maintenance. It also imposes real technical constraints. Our EDI connections run over SFTP and do not support AS2, so a partner requiring AS2 needs that resolved before anyone commits to a date.

When should you use an API?

Use an API when you need application-level access to data or functions, and the system exposes the endpoints you need.

Payment processing, shipping rates and labels, storefront and marketplace operations, product information, and customer-facing lookups all sit naturally on APIs. So does any interaction where you need to ask a question and act on the answer in the same moment.

An API is also the better fit when a supplier has built one and has no EDI capability at all, which is common among newer brands and smaller distributors.

Where APIs cost you: no shared standard, so each integration is bespoke, and no obligation on the provider to keep their interface stable. Version changes, deprecations, and rate limits are ongoing maintenance.

Which is better for a retailer, EDI or API?

For a retailer buying from multiple suppliers, EDI usually carries the buying relationship and APIs usually carry everything else.

The buying side, which means orders, acknowledgements, shipments, invoices, and inventory, tends to involve partners who already run EDI and expect you to meet their specification. Distributors and manufacturers have been doing this for decades and their processes are built around it.

The selling side, which means storefronts, marketplaces, payments, shipping, and customer experience, is almost entirely API territory.

The mistake we see retailers make is not picking the wrong technology. It is picking one technology and then forcing every supplier through it. That is how you end up either excluding good suppliers who cannot meet an EDI specification, or hand-processing the ones who will only send files.

Can EDI and APIs work together?

Yes, and in most working ecommerce operations they already do.

A realistic setup looks like this. Marketplace and storefront orders arrive through APIs. Order routing decides which supplier fulfills each one. Supplier A receives its purchase order as an EDI 850. Supplier B receives the same order through an API. Supplier C gets a file on SFTP. The shipping carrier is called through an API. The ERP receives the finished transaction.

Five connection methods, one workflow. The customer never sees the difference, and neither should your operations team. That is the actual goal: not technology consistency, but operational consistency across inconsistent partners.

We built supplier integration around that assumption, because requiring every supplier to standardize on one method is a requirement suppliers routinely decline.

How do you choose between EDI and an API?

Work through five questions in order.

1. Does the partner require a specific method? If yes, you are done. Their requirement wins.
2. What is being exchanged? Standardized business documents point to EDI. Application data and actions point to an API.
3. What timing does the business actually need? Define it in minutes or hours, then check what each option delivers.
4. What does the partner already support? The method they run today is almost always cheaper than the one they could build.
5. Who maintains it? Both need an owner for changes, failures, and onboarding.

Do not choose an API because it sounds current, or EDI because it sounds established. Choose the method that fits the relationship, and expect the answer to differ per supplier.

What should you do next?

If EDI is the right fit, Chapter 4 covers how to set it up and Chapter 3 covers the transaction codes. If you are connecting suppliers who each work differently, read multi-supplier EDI. For the API side of an ecommerce architecture, see our headless commerce API.

Frequently asked questions

Is EDI better than an API?
Neither is universally better. EDI fits standardized business documents and partner-mandated processes. APIs fit application-level data and actions. The right question is which one fits the specific relationship in front of you.

Can an API replace EDI?
Only if the trading partner supports the API and it meets the same business requirements. A partner's EDI requirement is a contractual condition, not a technical preference, so you cannot resolve it by choosing a different technology on your side.

Is EDI faster than an API?
Speed depends on the implementation, not the technology. An hourly EDI feed beats a daily API refresh. Ask any partner for their actual frequency rather than assuming from the category.

Why do ecommerce businesses use both EDI and API?
Because their partners do. Distributors and large retail partners tend to run EDI, while storefronts, marketplaces, payment processors, and carriers run APIs. Supporting both is what lets you work with all of them.

Is EDI being replaced by APIs?
No. Individual integrations move to APIs, but the underlying requirement for standardized documents between trading partners has not changed. Both continue to appear in the same architectures.

What is the difference between EDI and EAI?
EDI exchanges business documents with outside trading partners. Enterprise Application Integration connects applications inside your own organization. They solve different problems and often run alongside each other.