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How do I list an item using eBay product data?
Here is a general flow of how to list an item using eBay product data
Here are the order of steps you want to go through to list an item on eBay using product listing information,
1. Finding if a category requires product listing details. To do this, you need to make a GetCategoryFeatures API request, http://developer.ebay.com/DevZone/XML/docs/Reference/eBay/GetCategoryFeatures.html#Response.Category.ProductCreationEnabled. The values returned for this field will tell you what you need/can do.
2. Finding a product in the eBay catalog. Everything will be based from the FindProducts API, http://developer.ebay.com/DevZone/shopping/docs/CallRef/FindProducts.html. Here are some articles with some additional information.
Answer Title: Finding if UPC has a match in eBay's product catalog
Answer Link: https://ebaydts.com/eBayKBDetails?KBid=1630
Answer Title: FindProducts support for MPN
Answer Link: https://ebaydts.com/eBayKBDetails?KBid=1723
Answer Title: Listing items with product information using eBay catalog
Answer Link: https://ebaydts.com/eBayKBDetails?KBid=1829
3. If we don't have the product in our catalogs, there are two options,
A. If the categoy supports product creation, you can add the product to eBay,
Answer Title: Add products to eBay catalog
Answer Link: https://ebaydts.com/eBayKBDetails?KBid=1944
B. If the category does NOT support product creation, you want to make sure to fill in as much detail as you can in your listing (description, item specifics, etc). You also want to use this field so your item is listed without error,
4. Once you have or don't have the product listing information, you need to specify that information in the add item API call, http://developer.ebay.com/DevZone/XML/docs/Reference/eBay/AddFixedPriceItem.html#Request.Item.ProductListingDetails
Answer Title: Listing with Product Data
Answer Link: https://ebaydts.com/eBayKBDetails?KBid=1580
AddFixedPriceItem - http://developer.ebay.com/DevZone/XML/docs/Reference/eBay/AddFixedPriceItem.html