Cart recommendations

DesignHard50 minAmazon and Walmart style

Your task

Design a 'frequently bought together' and real-time cart/session recommendation system for a grocery-delivery app. Suggestions must update as items are added to the cart ('you added pasta, add sauce?'), reflect within-session intent, handle 100M products with massive popularity skew, and serve under 100ms as the cart changes.

It covers

  • Session based
  • Sequence model
  • Real time