System Design Cheatsheet

Single application with all components tightly coupled

Independent services communicating via APIs

Services communicate through events and messages

Functions as a service, no server management

Command Query Responsibility Segregation

Add more machines to distribute load

Add more resources to existing machine

Distribute traffic across multiple servers

Store frequently accessed data in memory

Split database into smaller parts

Multiple active nodes serving traffic

One active node, others on standby

Automatic switch to backup system

Copy data across multiple nodes

Prevent cascading failures

Atomicity, Consistency, Isolation, Durability

Basically Available, Soft state, Eventually consistent

Consistency, Availability, Partition tolerance

Data will be consistent eventually

Data is consistent immediately

Authorization framework

JSON Web Tokens for authentication

Secure communication over TLS

Limit requests per user/IP

Cross-Origin Resource Sharing

Content Delivery Network

Optimize query performance

Reuse database connections

Handle tasks in background

Reduce data transfer size