Problem
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[Instacart](https://leetcode.com/discuss/interview-question/system-design/657775/System-Design%3A-Design-Instacart)
System Design Instacart Customer Facing Portal / App

Customer Portal
Registration
Seller Component (Eg. Costco, Safeway)
Notifications on Registration and Order Fullfillment
Chat Server
Also design API that Seller (Costco) will use to call instacart to fullfill the order so that instacart can complete the order and later someone will go to costco to buy the products.

Requirements
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- Users module (register/authentication)
- Seller portal (register/upload products/read feed from vendors)

Traffic
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- 128M housholds
- 350k active shoppers / 7 days = 50k/day
-