Retrieves recommended items from categories related to a specified category or item. If categoryId is specified, then items are returned from categories related to the given category. If itemId is specified, then items are returned from categories related to the given item's category. In either case, the response contains items from the three best matching categories. The selection of items is evenly distributed between the best matching categories. The recommended items are sorted by end time, with items ending soonest first.
The request must contain either categoryId or ItemId. If both itemId and categoryId are specified, categoryId takes precedence.
Note: In some cases, the item recommendations returned by getRelatedCategoryItems are not closely related to the item specified in the request. Refer to the getRelatedCategoryItems does not return related items thread in the eBay Shopping and Merchandising API Production System Announcements board for more information, including an ETA for when this problem will be resolved.
Specifies the category used to determine related categories from which to retrieve item listings. This field takes the same category ID data as used with other eBay APIs.
Category IDs are site-specific. If the specified category ID doesn't match an existing category for the site, an invalid-category error message is returned. To determine valid categories, you can use either the Shopping API or the Trading API. In the Shopping API, use the FindItemsAdvanced call with the CategoryHistogram value in the IncludeSelector field to retrieve matching category information. In the Trading API, use calls like GetCategories and GetCategoryFeatures to determine valid values for the site.
See the Field Index to learn which calls use categoryId.