This comprehensive course prepares you for DoorDash software engineer interviews and DoorDash system design interview questions.

This course prepares you for a system design interview by using a case study of DoorDash (a prepared food delivery system) and familiarizes you with the challenges you will encounter during the interview. 

You will begin by understanding the theory behind the system design interview to give you an idea of what to expect. Next, you’ll understand how to identify a system’s requirements, handle data, and lay down the architecture of the system. Along the way, diagrams and quizzes will help you solidify your concepts.

By the end of this course, you will have a solid understanding of how to approach a system design interview, and you will have the confidence to answer a number of different scenarios, no matter the question.

System Design Interview: DoorDash

# Requirements and goals of the system

## Main actors in the system
1. Customers/consumers
2. DoorDashers (Drivers)
3. DoorDash Admin (from the company)
4. Restaurant (Merchant)


## Assumptions
* Unlimited food is available between the times a restaurant opens and closes. So there is no need to check  the quantity of available food. No inventory management is required.
* Restaurants don’t have their own online ordering system/infrastructure, they will solely rely on us for all orders.
* Customers will be shown restaurants within a particular radius, say 10 miles.
* Customers are allowed to order food from only one restaurant at a time in an online order. Menu items from multiple restaurants can’t be combined in an order.

## Functional requirements
### Customers should be able to: ####
* **search** for restaurants based on the cuisines type, menu items, etc;
* create a **cart**, add menu items to the cart and order;
* receive notifications about the **status** of an order once placed;
* **track** the _status_ of the order on the app;
* **cancel** the order;
* **pay** for the order;
* create/update their **account** and **contact information**
### Restaurants should be able to: ####

* create their **profile** (onboarding) and create, refresh and add new **menu items** and **pictures**;
* receive **notifications** about orders placed, assigned DoorDasher, and update the **status** of an order, etc;
* **do offboarding**, if the restaurant goes out of business or decides to discontinue taking online orders.
### DoorDashers should be able to: ####
* receive notifications about the **available orders** in the area, from which they can choose;
* know when the order is available for **pickup**;
* **inform** the customer/restaurant of any problems they encounter while executing the order pickup/delivery;
* **de-register** in case they don’t want to continue with the job anymore.


Let's identify the functional and nonfunctional requirements, goals, and capacity estimation of the DoorDash system.

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Identify Requirements, Goals & Capacity Estimation of the System

Requirements and goals of the system

Main actors in the system

Assumptions

Functional requirements

Customers should be able to: