How to Read a Smart Contract on Etherscan for Beginners?

Understanding the Basics of Smart Contract Verification

1. Smart contracts deployed on Ethereum are compiled into bytecode and stored on-chain, making raw inspection difficult without proper tools.

2. Etherscan serves as a public blockchain explorer that indexes transaction data, contract addresses, and source code when developers choose to verify and publish it.

3. Verified contracts display a green “Verified” badge next to the contract name, indicating that the submitted source code matches the deployed bytecode.

4. Unverified contracts only show bytecode or assembly, which is nearly impossible for non-experts to interpret meaningfully.

5. Verification requires matching compiler version, optimization settings, and input parameters — mismatches result in failed verification and untrusted code display.

Navigating the Contract Page Interface

1. After entering a contract address into Etherscan’s search bar, users land on a dedicated contract page with tabs like “Contract”, “Transactions”, “Analytics”, and “More”.

2. The “Contract” tab contains the most critical information: ABI, read/write functions, and the source code section if verified.

3. The “Read Contract” section allows interaction with view/pure functions without gas fees — users can query balances, token names, or ownership status directly.

4. The “Write Contract” section enables state-changing actions such as transferring tokens or updating permissions, but requires wallet connection and gas payment.

5. The “Contract Source Code” panel shows the original Solidity (or Vyper) files, often organized across multiple tabs if the project uses imports or libraries.

Interpreting Key Sections of Verified Source Code

1. The SPDX License Identifier appears at the top and signals legal usage terms — absence may indicate unreviewed or potentially risky code.

2. Compiler version pragma statements like pragma solidity ^0.8.20; must match the version used during deployment — mismatched versions risk unexpected behavior.

3. State variables declared with public visibility automatically generate getter functions, visible under “Read Contract”.

4. Modifier usage — such as onlyOwner or whenNotPaused — reveals access control logic critical for assessing centralization risks.

5. External function signatures expose how third-party dApps interact with the contract — unusual parameter types or undocumented events may signal obfuscation.

Recognizing Red Flags in Contract Code

1. Functions marked payable without clear business logic justification could enable unintended ETH transfers or reentrancy vectors.

2. Missing or generic event emissions reduce transparency — legitimate protocols emit events for every critical state change like minting or burning.

3. Use of selfdestruct or delegatecall without thorough documentation raises concerns about upgradeability and trust assumptions.

4. Hardcoded addresses instead of configurable parameters suggest inflexibility and potential manipulation points.

5. Absence of standard interfaces like ERC-20 or ERC-721, despite claiming compatibility, indicates deviation from audited patterns.

Frequently Asked Questions

Q: What does “Unable to verify” mean when I try to verify a contract?It means the submitted source code does not produce identical bytecode under the specified compiler settings — either due to version mismatch, optimizer differences, or incorrect constructor arguments.

Q: Can I trust a contract just because it shows “Verified” on Etherscan?No. Verification confirms code integrity, not correctness or safety — malicious logic can be fully verified and still harmful.

Q: Why do some contracts have multiple source code tabs?They use modular architecture with separate files for libraries, interfaces, or implementation contracts — each file is uploaded individually during verification.

Q: Is it possible to read unverified contract logic?Only through decompiled bytecode using tools like Mythril or evm-opcodes, but results are highly abstract and unreliable for functional understanding.