Businesses selling on marketplaces know the effect: two similar parts are online, one sells within days, the other sits for months. The difference is rarely the price and almost always that one appears in search and the other does not.
How a marketplace search works
Buyers search in three ways, and all three need a particular field:
| Search route | What the buyer enters | Which field is needed |
|---|---|---|
| Number search | The part number from their old part | OE number including predecessors |
| Vehicle search | Their vehicle by make, model or key number | Vehicle assignment, HSN/TSN, build period |
| Category search | A product group with filters | Article type and attributes, see GenArt number: what kind of part is this, actually? |
Miss a field and the corresponding search route drops out. A part without an article type appears in no category selection, a part without a vehicle assignment in no vehicle search — however well the description is written.
The fields practically every marketplace requires
- Article type and, depending on the product group, its attributes.
- Part numbers in a dedicated field, not in the description text. Free text is rarely indexed.
- Vehicle assignment, ideally with build period and engine.
- Condition on a fixed scale.
- Dimensions and weight for shipping calculation, see Shipping used parts: dimensions, packaging, transport damage.
- Images at sufficient resolution, see Part photography: how images sell used parts.
- Stock quantity and availability, reliably maintained.
Why the category so often misses
Marketplaces build their own category trees and map article types onto them. Sorting manually hits the obvious but not the searched-for category on half the parts — because the buyer thinks differently from the person listing. Assignment via the part number is therefore more reliable than picking from a dropdown.
In practice: capture the OE number, derive article type and attributes from it, and derive the marketplace category from the article type rather than from instinct. How the article type gets into stock is covered in Part identification: from removed component to sellable record.
One stock, several channels
As soon as a second channel appears, the question is where stock is kept. The answer is always: in one place. Two separately maintained lists diverge within weeks, and the result is the most expensive error in online trading — a sold part still on offer.
- Your own system leads, not the marketplace.
- Channels are served from it, by file or interface — see Connecting an API: when it pays off for dismantlers.
- Sales and reservations feed back, immediately and not in the evening.
- Returns are booked back in, with an updated condition.
What does not belong in the data
Finally the other side: fields you cannot substantiate stay empty. An estimated offset, an inferred equipment variant or a probable cross reference improve visibility — and produce exactly the returns that eat that visibility again.
Frequently asked
Why is my listing not found?
Usually a search field is missing: the part number sits in prose instead of the number field, the article type is absent, or there is no vehicle assignment.
Should I give predecessor numbers?
Yes, and in the number field. Buyers search with the number on their old part, and that is often the older one in the chain.
How do I avoid double sales across marketplaces?
By keeping stock in one place only and serving the channels from it. Separately maintained lists inevitably diverge.
Is more always better with data fields?
No. A field filled by estimate brings visibility and returns at once — and the return costs more than the visibility brought in.