EDI or API? How department stores and marketplaces want to connect in 2026
Department stores still run wholesale on EDI, while marketplaces build their partner programmes on APIs. Fashion brands increasingly need both, connected to one clean set of ERP and product data.
KEY TAKEAWAYS Summary by the editors
- EDI and APIs are not rivals in fashion wholesale: department stores still define their supplier requirements in EDI documents, while marketplace platforms are built around APIs.
- Nordstrom, for example, requires suppliers to exchange the X12 850 purchase order, 856 advance ship notice, 810 invoice and 997 acknowledgement.
- Zalando's zDirect platform describes itself as a RESTful API covering partner integration, including products, prices, stock, orders and logistics.
- E-invoicing mandates add a third channel: since 1 January 2026 Belgian VAT-registered businesses must exchange structured domestic B2B invoices, implemented through Peppol.
- The practical decision for a brand is less EDI versus API than where to place one integration layer that serves both from the same ERP and product data.
In 2026 most department stores still expect fashion brands to connect through EDI, while marketplaces and platform partner programmes expect APIs. A brand that sells through both therefore needs both, and the real question is how to run them from one consistent set of order, stock and product data. Choosing a side is rarely an option; choosing a sound integration architecture is.
What is the difference between EDI and an API?
EDI is the exchange of standardised business documents, such as orders, despatch advices and invoices, in formats agreed across an industry, typically EANCOM in Europe and ANSI X12 in North America. An API is a programmable interface that one system exposes so another can request or send data, usually in real time and in a format defined by the platform owner. SPS Commerce summarises the distinction as batch processing for EDI against real-time data movement for APIs, and stresses that the two are not exclusive: it notes that most modern EDI solutions are themselves API driven.
| Aspect | EDI | API |
|---|---|---|
| Format | Industry standard documents (EANCOM, X12) | Defined by each platform |
| Timing | Usually batch, files sent at intervals | Usually real time or near real time |
| Typical partners | Department stores, chains, distributors | Marketplaces, platforms, drop ship programmes |
| Strength | Stable, legally and commercially established, one standard for many partners | Fast, granular, suits stock and price updates |
| Weakness | Retailer-specific variations, slower change | Each platform needs its own integration and maintenance |
| Data typically exchanged | Orders, order responses, ASNs, invoices | Products, prices, stock, orders, shipments |
How do department stores want brands to connect?
Department store supplier requirements are still written in EDI terms. Nordstrom's supplier compliance programme, as summarised by SPS Commerce in June 2025, requires suppliers to be EDI enabled within 60 days of initial setup and names the 850 purchase order, 856 advance ship notice, 810 invoice and 997 functional acknowledgement. It also requires ASNs to match both the shipment and the purchase order to store and SKU level. These are document-based, compliance-driven relationships, and the retailer's system of record expects documents in its format.
For a brand, the advantage is predictability: once an EANCOM or X12 mapping exists in the ERP, a new department store account often needs adjustments rather than a new build. The disadvantage is that each retailer's implementation guide adds its own rules, so a standard is never entirely standard.
How do marketplaces and platforms want brands to connect?
Marketplaces design their integrations around APIs because they need frequent updates of stock and price across very large assortments. Zalando's zDirect developer documentation describes a RESTful API that covers all stages of partner integration, including submitting and validating products, setting prices, managing stock, fulfilling orders and tracking shipments to and from Zalando warehouses. Partners can choose to fulfil orders themselves or use Zalando's fulfilment services.
Here the hard part is not the protocol but the product data. A marketplace API will reject products with missing attributes, and stock updates are only useful if the brand's available-to-sell figure is reliable. Brands that send the same stock to wholesale accounts, their own webshop and marketplaces need clear allocation rules to avoid overselling.
APIs also change the operating rhythm. An EDI order arrives as a document and is processed in a batch; an API integration expects the brand's systems to answer requests at any time and to push updates whenever stock or prices change. That demands monitoring outside office hours, clear rate and error handling, and a plan for platform version changes, which are announced by the platform owner rather than agreed through a standards body.
Where do e-invoicing mandates fit in?
Tax rules are adding a further connection type. According to VATCalc, since 1 January 2026 Belgian-established VAT taxpayers must issue and receive structured e-invoices for domestic B2B transactions, as XML based on the European standard EN 16931 and exchanged through the Peppol network, with e-reporting to follow from 2028. For brands that already send EDI invoices to retailers, this means checking whether those flows meet local legal requirements or whether a Peppol route is needed alongside them.
How should a fashion brand decide between EDI and API?
The decision is usually made for you by the partner. What a brand does control is the architecture behind it. Four questions help:
- Where does the truth live? Orders, stock and prices should come from one ERP or order management system, not be re-keyed per channel.
- Who maintains the connectors? An EDI provider, an integration platform or in-house IT, with clear responsibility for retailer specification changes.
- How fresh must the data be? Marketplace stock needs frequent updates; a seasonal pre-order to a department store does not.
- How are errors handled? Both EDI rejections and API errors need monitoring, alerting and an owner.
What does this mean for ERP and integration planning?
A brand selling through department stores, specialist retail and marketplaces will typically run EDI for the first two and APIs for the third, plus e-invoicing where required. The integration layer between ERP and partners should translate one internal data model into each partner's format. When that layer is missing, every new account becomes a custom project, and errors multiply because the same data is maintained in several places. Before choosing tools, map which partners use which standard today and which are likely to change in the next two years.
A practical first step is a simple inventory: list each retail and platform partner, the standard or API it uses, the documents or endpoints in scope, the volume per season and who maintains the connection. That overview usually shows where the same data is keyed twice and where a shared integration layer would remove the most manual work.
Frequently asked questions
Is EDI being replaced by APIs?
Not in fashion wholesale for now. Department stores still publish EDI-based supplier requirements, while marketplaces use APIs. Most brands need both, and many EDI services now use APIs internally.
Does Zalando use EDI or API for partners?
Zalando's zDirect platform documentation describes a RESTful API covering products, prices, stock, order fulfilment and logistics for partners. Brands should check the current documentation and their own contract for the exact integration options available to them.
What is Peppol and why does it matter for fashion brands?
Peppol is a network and set of specifications for exchanging structured e-documents such as invoices. Belgium has required structured domestic B2B e-invoices via Peppol since 1 January 2026, so brands invoicing Belgian customers need a compliant route.
Which is cheaper, EDI or API integration?
It depends on the number of partners and how standardised they are. EDI reuses one standard across many retailers but carries provider and mapping costs; each API integration is built per platform and must be maintained when the platform changes.
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