System requirements
Functional:
User authentication
Search tweets
Tweet
Notifications
Timeline
Like/favorites
Follow users
Non-Functional:
Scalable - design the system to handle a large number of potential users by utilizing cloud provider such as AWS
Reliability
Performance
Capacity estimation
On average each user tweet, 10 times a day. With each tweet being around 200 characters and each character costing 4 bytes. So each user uses 8000 bytes a day. Which means 1 million users uses 8 terabytes per day.
Efficient data storage. Data partition, caching would be needed in our design.
API design
/create Tweet
/Get tweets
/Get timeline
/Like
/Favorite
/Login
/Signup
/Logout
/Comment
Database design
Tweet
User
Comment
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...
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?