System requirements

Functional:

CRUD for parking lot - admin

CRUD for parkinglevel - admin

CRUD for parkingspot - admin

status for parkingspot - customer/ parking attendant

CRUD for reservation - customer

payment (3rd party)

Non-Functional:

strong consistent (tradeoff: latency)

durable

Capacity estimation

Estimate the scale of the system you are going to design...

I will not anticipate much scaling issues with this problem

API design

Define what APIs are expected from the system...

I will go ahead with the REST API for this problem, while utilising some caching to save elements that aren't changed as much like total number of spots per level etc

Database design

Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...

ParkingLot:

id: int, serial

zipcode: string (can be used for sharding in case of scaling)

totalAvailableSpots: int

ratePerCompact: decimal

ratePerRegular: decimal

ratePerLarge: decimal

Not mapped:

List

ParkingLevel:

id: int, serial

parkingLotId: int, FK

totalCompactSpots: int

totalRegularSpots: int

totalLargeSpots: int

ParkingSpot:

id: int, serial

parkingLevelId: int, FK

Status: enum: Available/Booked/NotInService etc

VehicleType: enum: Compact/Regular/Large/Electric etc

Reservation: (1 to 1 relation for both FKs)

id: int/ guid

parkingLotId: int, FK

parkingSpotId: int, FK

startTime: timetamp

endTime: timestamp

High-level design

You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design. If you are unfamiliar with the tool, you can simply describe your design to the chat bot and ask it to generate a starter diagram for you to modify...

Request flows

Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...

Detailed component design

Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...

Trade offs/Tech choices

Explain any trade offs you have made and why you made certain tech choices...

Failure scenarios/bottlenecks

Try to discuss as many failure scenarios/bottlenecks as possible.

Future improvements

What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?