poojakittur/sd4

System Design 4

Designing a service like Facebook Messenger

What to be designed?

1. Facebook Messenger is a software application that provides its users with text-based, instant messaging services.
2. Messenger users can chat from both cell phones and Facebook's website with their Facebook friends.
3. Let's build an instant messaging service like Facebook Messenger where users can send each other text messages through web and mobile interfaces.

Feature Requirements

Primary Features:

1. Messenger should support conversations between users on one-on-one basis.
2. Messenger should support continued chat history storage.
3. Messenger will keep track of its users' online / offline statuses.

Secondary Requirements:

1. Users should experience chatting in real time with minimal latency.
2. Our system should be highly consistent; users should be able to see all their devices having the same chat history.
3. High availability by Messenger is desirable; in the interests of consistency we can tolerate lower availability.

Extended Features:

1. Group Chats
2. Push notifications

TO DO : Follow the below framweork to design System. Mandatory upload of hand drawn photos of design.

Capacity Estimation and Constraints

What will your estimations of scale? As a system design student you should be able to make intelligent assumptions based on real life systems.

System APIs

Database Design

Basic System Design and Algorithm

Data Partitioning and Replication

Caching

Load Balancing

Handling Edge cases in given system