- ---
- order: 1
- parent:
- title: ABCI++
- order: 3
- ---
-
- # ABCI++
-
- ## Introduction
-
- ABCI++ is a major evolution of ABCI (**A**pplication **B**lock**c**hain **I**nterface).
- Like its predecessor, ABCI++ is the interface between Tendermint (a state-machine
- replication engine) and the actual state machine being replicated (i.e., the Application).
- The API consists of a set of _methods_, each with a corresponding `Request` and `Response`
- message type.
-
- The methods are always initiated by Tendermint. The Application implements its logic
- for handling all ABCI++ methods.
- Thus, Tendermint always sends the `Request*` messages and receives the `Response*` messages
- in return.
-
- All ABCI++ messages and methods are defined in [protocol buffers](../../proto/tendermint/abci/types.proto).
- This allows Tendermint to run with applications written in many programming languages.
-
- This specification is split as follows:
-
- - [Overview and basic concepts](./abci++_basic_concepts_002_draft.md) - interface's overview and concepts needed to understand other parts of this specification.
- - [Methods](./abci++_methods_002_draft.md) - complete details on all ABCI++ methods
- and message types.
- - [Requirements for the Application](./abci++_app_requirements_002_draft.md) - formal requirements
- on the Application's logic to ensure liveness of Tendermint. These requirements define what
- Tendermint expects from the Application.
- - [Tendermint's expected behavior](./abci++_tmint_expected_behavior_002_draft.md) - specification of
- how the different ABCI++ methods may be called by Tendermint. This explains what the Application
- is to expect from Tendermint.
-
- >**TODO** Re-read these and remove redundant info
-
- - [Applications](../abci/apps.md) - how to manage ABCI application state and other
- details about building ABCI applications
- - [Client and Server](../abci/client-server.md) - for those looking to implement their
- own ABCI application servers
|
