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Debugging with Sentio

Learn how to install and use the Sentio plugin in BuildBear to debug and analyze smart contract transactions.

What is Sentio?

Sentio is a smart contract debugging tool that gives developers granular insights into contract execution. With deep, line-by-line analysis capabilities, it enables precise identification and resolution of complex blockchain development issues.

What You'll Learn

  • How to install and configure the Sentio plugin in a BuildBear sandbox
  • How to debug ERC-4337 User Operations
  • How to analyze call traces, fund flows, call graphs, and gas usage

Key Features

Comprehensive Transaction Analysis

  • Balance Changes: Track token balances across each transaction step.
  • Fund Flow: Visualize token flows across contracts.
  • Call Trace & Call Graph: Inspect contract call structure and relationships.
  • Gas Profiler: Analyze gas usage by function and trace for optimization.
  • State & Events: See contract state changes and emitted events.

Visual Debugging Interface

  • Graphical dashboards simplify blockchain data interpretation.
  • Step-through debugging (Step-Into, Step-Over, Step-Out)
  • Direct access to opcode traces, inputs, and gas reports

Step 1: Set Up Your Sandbox

  1. Create or open an existing BuildBear sandbox.
  2. Navigate to the Plugins tab.
  3. Find and install the Sentio Plugin.

Plugin Installation

After installation, you'll be able to see "View Tracer" or "Debug with Sentio" buttons in your sandbox transaction explorer.

Step 2: Analyze a Transaction

What is a User Operation?

A UserOp (User Operation) in ERC-4337 allows users to initiate transactions through a smart contract (EntryPoint) instead of a traditional wallet. This enables advanced functionality like sponsored transactions and modular account logic.

We will debug a UserOp on BuildBear to explore Sentio's capabilities.

Exploring Sentio Tabs

Fund Flow

Shows sender, receiver, intermediate contracts, and how tokens moved during the transaction. Fund Flow

Call Trace

Line-by-line breakdown of smart contract execution paths. Call Trace

Call Graph

Graphical representation of function calls across different contracts. Call Graph

Gas Profiler

Provides gas limit, actual usage, and function-level breakdowns. Gas Profiler

Debugger

Detailed opcode view with step-through capabilities. Inspect sender/receiver, calldata, opcodes, and gas metrics.

Sentio Debugger

Contracts

List of all smart contracts that interacted in the transaction. Contracts

Events

Event logs emitted during execution. Events

State

Displays state changes in storage slots across contracts and EOAs. State Changes

Conclusion

Sentio enhances your debugging workflow with deep introspection tools for smart contracts. From fund flow to opcode-level debugging, it gives developers everything they need to build with confidence.