Application Blockchain Interface (ABCI) is a protocol that allows communication between a blockchain network and its applications. It functions as a bridge, enabling the blockchain to interact with off-chain systems or services.ABCI separates the application logic from the blockchain layer, which makes it easier to develop, modify, and scale applications. This modular design enhances the flexibility of how blockchains can be used, allowing developers to create various types of applications without needing to alter the core blockchain architecture.Using ABCI, applications can send and receive messages, execute transactions, and manage state changes, while the blockchain takes care of consensus and data integrity. This approach leads to improved performance and efficiency, as it allows applications to run independently and potentially utilize different programming languages or frameworks.Overall, ABCI provides a structured way for developers to create innovative applications that can leverage the benefits of blockchain technology without being confined to a single programming environment or structure.