Smart Contract Explorer

WHAT IT DOES

The Smart Contract Explorer is a read-only developer tool that gives you a quick technical overview of any Ethereum address. Enter a contract address and the app fetches the bytecode, ETH balance, and transaction count. It then determines whether the address is a contract or an externally owned account (EOA). For contracts, it displays the bytecode size and a heuristic ABI detection that extracts potential function selectors from the bytecode. It also simulates verification status to indicate whether the contract is likely verified (based on bytecode length). This is useful for developers auditing contracts, security researchers performing quick inspections, or anyone who wants to understand what a contract does without opening a full block explorer.

HOW TO USE

1. Select your network from the dropdown or connect your wallet to use its RPC endpoint.

2. Enter the contract address you want to explore.

3. Click "Explore contract" to fetch the data.

4. Review the results: address, contract type (contract or EOA), bytecode size, ETH balance, and transaction count.

5. Check the simulated verification status (based on bytecode presence and length).

6. Scroll down to see the bytecode preview (first 500 characters) and the ABI section, which lists potential function selectors extracted from the bytecode.

7. Use the "Clear" button to reset the form and explore another contract.

ONE TECHNICAL SECTION

The most interesting technical aspect of this tool is its heuristic ABI detection. When a contract is not verified on a block explorer, there is no straightforward way to know its ABI — the interface is not stored on-chain in a human-readable format. However, the bytecode contains function selectors: the first 4 bytes of the Keccak-256 hash of the function signature. These selectors are embedded in the bytecode and can be extracted by scanning the bytecode for patterns that look like selector data. This tool implements a simple heuristic that scans the bytecode for 8-character hexadecimal strings (4 bytes) and deduplicates them, presenting the most common ones as potential function selectors. While this is not a full ABI and cannot reconstruct function names or argument types, it provides a starting point for reverse-engineering or for matching selectors against known signatures. This approach is particularly useful for analyzing unverified contracts where no other interface information is available.

WHAT IT CANNOT SEE

This tool cannot decompile obfuscated or optimized bytecode. Solidity's optimizer, inline assembly, and other compiler features can make bytecode extremely difficult to analyze without full source code. It cannot recover original source code from unverified contracts — only the bytecode is available on-chain, and source code recovery is a separate, complex decompilation process. The tool cannot verify the correctness or security of contract logic; it only shows raw data. The ABI detection is heuristic and may produce false positives or miss selectors entirely. The tool is limited by RPC archive data availability and block explorers' verification APIs — if the RPC does not support historical state, some data may be missing. It cannot prove that the deployed bytecode matches the published source code or detect malicious modifications in unverified contracts.

PLEASE NOTE

This tool works only with EVM-compatible