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ABCI Flows

Introduction​

This page provides comprehensive technical diagrams that visualize the core architectural components and transaction flows within CrossFi Chain. The diagrams focus on the Application Blockchain Interface (ABCI), demonstrating how transactions are processed, validated, and executed through the interaction between Tendermint consensus, Cosmos SDK modules, and the integrated Ethereum Virtual Machine (EVM). Both EVM transactions (smart contracts) and native Cosmos transactions (staking, governance, transfers) are covered, highlighting the dual nature of CrossFi's execution environment.

These technical visualizations serve as essential reference materials for developers, validators, and technical stakeholders who need to understand the internal workings of CrossFi Chain's modular architecture.

ABCI Transaction Flow Diagram​

The following sequence diagram illustrates the complete lifecycle of a transaction in CrossFi Chain, from user initiation through final confirmation. This flow demonstrates how CrossFi's hybrid architecture processes both EVM and Cosmos transactions through the same ABCI interface while maintaining compatibility with both ecosystems.

Event Processing Architecture​

This diagram shows how CrossFi Chain handles different types of events generated during transaction execution. The architecture demonstrates the parallel processing of EVM events (compatible with Ethereum tooling) and Cosmos SDK events (native to the Cosmos ecosystem), providing developers with multiple interfaces to access blockchain data.

CheckTx vs DeliverTx: Key Differences​

This diagram illustrates the fundamental difference between the two main ABCI methods in CrossFi Chain. CheckTx performs lightweight validation to determine if a transaction should be accepted into the mempool, while DeliverTx executes the transaction and modifies the blockchain state. Understanding this distinction is crucial for developers working with CrossFi's transaction processing pipeline.

ABCI Method Lifecycle​

This state diagram shows the sequential execution of ABCI methods during block production in CrossFi Chain. Each block follows this precise sequence: BeginBlock initializes the block context, multiple DeliverTx calls process individual transactions, EndBlock finalizes block-level operations, and Commit persists the state changes to disk.

EVM and Cosmos Integration via ABCI​

This comprehensive diagram illustrates how CrossFi Chain integrates the Ethereum Virtual Machine with Cosmos SDK modules through the ABCI interface. The architecture shows how Tendermint consensus communicates with the application layer, which then routes transactions to either EVM execution (for smart contracts) or native Cosmos modules (for staking, governance, and transfers).

Event Types in CrossFi Chain​

EVM Events (accessible via JSON-RPC)​

  • Transfer events (ERC-20)
  • Approval events
  • Custom contract events
  • Contract creation/destruction
  • Gas usage metrics

Cosmos SDK Events (accessible via Tendermint WebSocket/gRPC)​

  • message.action - type of executed message
  • transfer.recipient - token recipient
  • transfer.amount - transfer amount
  • coin_received/coin_spent - token operations
  • delegate/unbond/redelegate - staking events
  • proposal_submit/proposal_vote - governance events

Error Handling in ABCI​

This flowchart demonstrates how CrossFi Chain handles different types of transaction failures at both the validation (CheckTx) and execution (DeliverTx) stages. Understanding error handling is essential for developers building robust applications on CrossFi Chain.

CrossFi Chain Performance Characteristics​

Key Performance Metrics:

  • Block time: ~5 seconds (with potential reduction to 1 second)
  • Throughput: Up to 10,000 transactions per second (TPS)
  • Finality: 1 block (instant finalization)
  • Validators: Up to 128 active validators

These performance characteristics make CrossFi Chain suitable for high-frequency DeFi applications and enterprise use cases that require fast transaction processing and immediate finality.

Conclusion​

These technical diagrams provide a comprehensive view of the ABCI transaction flows within CrossFi Chain. The ABCI diagrams demonstrate how CrossFi successfully integrates EVM and Cosmos SDK functionality through a unified interface.

For developers building on CrossFi Chain, understanding these flows is essential for:

  • Optimizing transaction processing and gas usage
  • Implementing proper error handling and event monitoring
  • Integrating with both EVM and Cosmos ecosystems

The combination of fast finality, high throughput, and interoperability makes CrossFi Chain a powerful platform for next-generation decentralized applications.