Application Blockchain Interface (ABCI)
Web3 / infrastructure applications
The Application Blockchain Interface is a technical specification that defines how a blockchain consensus engine communicates with application-level code, most commonly implemented in the Tendermint consensus framework. ABCI enables developers to build blockchain applications in any programming language by providing a standardized protocol for transmitting transactions and state changes between the consensus layer and the application layer. This abstraction separates consensus logic from application logic, allowing developers to focus on business rules while the consensus engine handles agreement and finality. Example: Cosmos SDK applications use ABCI to connect their custom state machines to Tendermint's consensus engine, allowing validators to agree on application state changes across the Cosmos network. Why it matters for blockchain infrastructure: ABCI democratizes blockchain development by decoupling consensus from application logic, reducing the technical burden on developers. This modularity has enabled the rapid proliferation of diverse blockchain applications and fostered ecosystem growth by allowing teams to build domain-specific chains with standard infrastructure.
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