Auto-Generated Sequence Diagram from Contract Calls

WHAT IT DOES

This tool auto-generates sequence diagrams from smart contract call patterns by analyzing on-chain transaction traces and historical interactions. It extracts call sequences from transaction traces, mapping the flow of calls between contracts, users, and internal functions. The tool visualizes these interactions as a structured sequence diagram showing the chronological order of calls, returns, and internal operations. Results are presented as a detailed sequence diagram with step-by-step call flows, participant lifelines, activation bars, and call/return arrows. This is essential for developers understanding contract interaction flows, auditors analyzing contract behavior, and teams documenting system architecture.

HOW TO USE

Connect your wallet (read-only, no transaction required) and select the target network. Enter the contract name and address, optionally provide a sample transaction hash for focused analysis, and set the lookback blocks for call pattern analysis. Click "generate sequence diagram" and the tool will verify the contract, analyze transaction traces and call patterns, and generate a structured sequence diagram. Results display a summary with contract details and step count, a text-based sequence diagram showing the full call flow with participants and arrows, detailed step cards showing each call with its participants and description, and a table of all steps. Use the report to understand contract interaction flows, document system behavior, and identify call patterns.

TECHNICAL MECHANISM

The generator uses ethers.js v5.7.2 to perform a multi-stage sequence diagram generation process. First, it calls eth_getCode to verify the contract is deployed and uses block explorer APIs to fetch verification status and ABI. The tool then retrieves transaction traces using debug_traceTransaction (when available) or analyzes historical logs via eth_getLogs across the specified block range to reconstruct call patterns. It extracts call sequences from the trace data, identifying participants (users, contracts, internal functions), call types (external, internal, delegatecall), and return flows. The tool maps function signatures from the ABI to human-readable names. It constructs a sequence diagram by ordering calls chronologically, drawing lifelines for each participant, and placing call/return arrows with activation bars. The diagram is represented both as a text-based visualization and a structured data model. Results are compiled into a structured report with detailed sequence information, participant lifelines, call arrows, and activation bars.

WHAT IT CANNOT SEE

This tool cannot generate diagrams for contracts that are not verified or have opaque implementation details where call patterns cannot be resolved. It is limited by the RPC provider's rate limits and availability of debug_traceTransaction, which may be restricted on some providers (e.g., rate-limited, disabled, or only available for archival nodes). It cannot capture call sequences for transactions that have not been executed or are pending. The analysis relies on the accuracy and completeness of transaction trace data and contract verification; incomplete traces or missing transaction data may produce incomplete diagrams. It cannot analyze call patterns for contracts that use delegatecall or proxy patterns without full trace data, as these patterns may obscure the actual call hierarchy. The tool is limited to the specific transactions and contract instances that are accessible via RPC. It cannot guarantee that generated diagrams capture all possible interaction paths without exhaustive transaction analysis across a large number of transactions. The diagram is a representation of observed call patterns and may not reflect all possible contract interactions.

PLEASE NOTE

This is a read‑only analytics tool—it never submits transactions or modifies contract state. It is designed for EVM‑compatible chains and works best with verified contracts and providers that support debug_traceTransaction. The generated sequence diagrams are for informational and documentation purposes only and should not be considered a comprehensive behavioral analysis. Always verify call patterns against actual contract behavior and test edge cases. The tool's diagram generation is heuristic and based on observed call patterns—customize or refine the output as needed for your specific documentation requirements.