Blockchains are systems for multi-master state machine replication. ABCI is an interface that defines the boundary between the replication engine (the blockchain), and the state machine (the application). Using a socket protocol, a consensus engine running in one process can manage an application state running in another.

Previously, the ABCI was referred to as TMSP.

The community has provided a number of additional implementations, see the Tendermint Ecosystem

To get up and running quickly, see the getting started guide along with the abci-cli documentation which will go through the examples found in the examples directory.

A detailed description of the ABCI methods and message types is contained in:

• The main spec
• A protobuf file
• A Go interface

To compile the protobuf file, run (from the root of the repo):

make protoc_abci

See protoc --help and the Protocol Buffers site for details on compiling for other languages. Note we also include a GRPC service definition.