I don't believe we can upload products to recommendations engine directly as this behavioral data is collected in real time by the algorithm used in the recommendations activity. You can however use feeds to upload products in recommendations before creating the activity to create a catalog for usage. You may find information in the following document helpful for that : Feeds
Thank you for the reply.
Yes, we are considering to use the CSV Feed method to upload product info.
But in some places of Adobe Target documention, we find mention of API based product upload. And hence wanted to check on it.
The final question in the FAQ and "Implementing Multi-value attributes" talk about using API to insert products.