What is CAP?

CAP Theorem, also known as Brewer's theorem, states that it is impossible for a distributed data store to simultaneously provide more than two out of the following three guarantees: Consistency (all nodes see the same data at the same time), Availability (every request receives a response, without guarantee that it contains the most recent version of the information), and Partition tolerance (the system continues to operate despite arbitrary partitioning due to network failures). When designing a distributed system, one must choose two of these three guarantees. Common trade-offs include CA (Consistency and Availability), AP (Availability and Partition tolerance), and CP (Consistency and Partition tolerance).