InventoryAPI by Erply is a powerful backend for web shops, and more.
This is a list of all product related API functions. Click on function name and you'll find all required and optional input parameters and response fields.
getProductCategories, hierarchical), brands (
getBrands, a flat list), and priority groups (
getProductPriorityGroups, a flat list)
images), so if you need to query product information anyway, getProducts can also provide you the list of images for each product.