Copycat is a fault-tolerant state machine replication framework. Built on the Raft consensus algorithm, it handles replication and persistence and enforces strict ordering of inputs and outputs, allowing developers to focus on single-threaded application logic. Its event-driven model allows for efficient client communication with replicated state machines, from simple key-value stores to wait-free locks and leader elections. You supply the state machine and Copycat takes care of the rest, making it easy to build robust, safe distributed systems.

Simple

Copycat's simple but powerful programming model allows single-threaded state machines to be transparently scaled across a cluster.

Sophisticated

Copycat is built on one of the most advanced implementations of the Raft consensus algorithm, supporting membership changes, incremental compaction, snapshots, session-based client communication, state machine events, and more.

Scalable

Copycat clusters are resilient to failure and can be scaled to virtually any size, and read capacity can be scaled independently of write capacity.

Reactive

Copycat's event framework allows for efficient, wait-free interaction with replicated state machines while maintaining the same fault-tolerance and consistency guarantees.

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