12-Factor App and CAP Theorem.

1. 12-Factor App:

A set of best practices for building scalable, portable, and manageable cloud-native applications. Key factors include:

• Codebase: One codebase, multiple deploys.
• Config: Store config in the environment.
• Backing Services: Treat DBs/Queues as attached resources.
• Statelessness: Processes should be stateless.

2. CAP Theorem:

In a distributed system, you can only have 2 out of 3:

1. Consistency: Every read receives the most recent write.
2. Availability: Every request receives a response (not necessarily the latest).
3. Partition Tolerance: The system continues to operate despite network partitions.

Key Insight: In our world, network partitions happen. So we must choose between CP (Consistency) or AP (Availability).