OTTO MOIN, product reference and SKU explained

Which identifiers exist on the OTTO marketplace?

Selling on otto.de means juggling several numbers at once. Some you assign, others OTTO assigns. According to the OTTO Market API (Products interface, version 5), the main ones are:

• SKU – your own identifier for a product variation.
• Product reference (productReference) – your identifier for the product that groups all its variations.
• EAN – the product's external article number (GTIN).
• MOIN – the identifier OTTO generates for the variation.

On top of that there's the product ID shoppers see in the address of every otto.de product page. Knowing which number does what helps you find products faster, avoid upload errors and attribute your rankings correctly.

What is the MOIN?

According to the API documentation, the MOIN is an identifier generated by the OTTO marketplace for a product variation together with its content. It's used for "Wettbewerb am Artikel" (competing on the same item): if another seller already offers the product, you confirm the existing content with the MOIN and put your own offer live for that variation. The documentation's example format is M00A1234BC.

The help centre of software vendor PlentyONE describes the flow: if the product is already sold on OTTO, your variation gets the existing MOIN; if it's new, OTTO creates one. According to Lengow, OTTO doesn't match automatically by EAN. If a similar product is already listed by another seller, OTTO returns the error "700001 – MOIN_ALREADY_KNOWN". Check whether it really is the same product, then confirm the offer or raise a ticket with OTTO.

What is the product reference?

The API documentation says the product reference groups all variations you want to combine into one product – say, a T-shirt in five sizes and three colours. Shoppers never see it, you can choose it freely, and it can be up to 50 characters long. Each product reference may be used only once in your catalogue, so OTTO recommends a value that fits all variations and doesn't describe one of them – not "Shirt-Blue-M", for example.

Note: per the API best practices, once a product reference and SKU combination for an EAN has been created successfully, it can't simply be changed. You have to deactivate the affected SKUs and resend the data. More on grouping in Setting up variations on OTTO.

SKU and EAN: your own numbers

• SKU: mandatory, up to 50 characters, unique within your seller account, no leading or trailing spaces. The API uses the SKU to address a variation for price, stock or status.
• EAN: must be unique in your assortment and, per the API documentation, must not start with a 2.

The SKU is your article number, not OTTO's. When a customer or your support team talks about "the article number", it's worth checking which one they mean.

The S0… ID in the otto.de address

Every otto.de product page has an address like otto.de/p/product-name-S0XXXXXX/. The string at the end starting with "S0" is the product page ID. When a specific variation is selected, otto.de also adds ?variationId=…. The text in front comes from the product title.

The MOIN doesn't appear in that address, but you can open any MOIN directly: https://www.otto.de/p/?moin= followed by the MOIN redirects to the matching product page. In our test in October 2026 this worked. It's a quick way to check whether a product is online and what its page looks like.

Where do you find the MOIN and product reference?

1. Product export in OTTO Partner Connect: the export of your product overview includes columns such as product reference (Produktreferenz), SKU, EAN, MOIN, marketplace status and "Link zu otto.de". The link looks like https://www.otto.de/p/?moin=….
2. Marketplace status via the API: each variation's status includes SKU, MOIN, status (for example ONLINE or REJECTED) and a link to the product in the OTTO shop.
3. Product overview in the portal: per the API documentation, that's where you'll find the product reference, among other things.

The API best practices recommend regularly checking that the MOIN you store per SKU matches the one in the marketplace status.

Why identifiers matter for rank tracking

To track positions you need to recognise your product reliably in the search results. Titles change, and so do images – identifiers stay stable. That's why MarktRank reads the product export from Partner Connect and links each product to its otto.de page via the MOIN. You measure the position of exactly the product you sell, organic and sponsored – see OTTO ranking: overall, organic, ad position. If other sellers offer the same item, keep an eye on them too – see Competitor research on OTTO.

Frequently asked questions