Explain the CAP Theorem.
Updated Apr 28, 2026
Short answer
In a distributed system, you can only guarantee two out of three: Consistency, Availability, and Partition Tolerance.
Deep explanation
Intermediate reliability engineering involves handling distributed failures and defining metrics. In a distributed system, you can only guarantee two out of three: Consistency, Availability, and Partition Tolerance.
Real-world example
A mobile app retrying to connect to a server when the signal is weak.
Common mistakes
- Retrying indefinitely without a cap, which can crash the server when it comes back up.
Follow-up questions
- What are the three states of a Circuit Breaker?