What is a recommender system?

A recommender system is software that decides which products, content or messages to show each person, based on their behavior, what they tell it directly and what similar customers chose.

A recommender system decides what to show each person: the products in a “you might also like” row, the order of search results, the stories in a feed, the next video, or which offer goes into an email. It learns from behavior such as clicks, views and purchases, from what people tell it directly, and from what similar customers did.

At RecSys 2026 the definition widened. Google, Target, Spotify and Infobip showed systems that write or assemble the recommendation itself, such as a news summary, a notification, a meal plan with a shopping list, or a full basket from a single request.