Mainnet Fork State Diff Inspector

WHAT IT DOES

Mainnet Fork State Diff Inspector is a read-only developer tool that inspects state differences between two blocks on a mainnet fork. It reads the contract address, pre-fork block number, post-fork block number, contract bytecode at both blocks, storage slots at both blocks, account balances at both blocks, transaction traces (simulated), state trie diffs (simulated), and previous diff records. The tool then generates a detailed diff report showing what changed between the two blocks for the specified contract, helping developers understand the impact of transactions or deployments on contract state.

HOW TO USE

Connect your wallet via the built-in connector. Select the network where the contract is deployed. Enter the contract address you want to inspect, the pre-fork block number, and the post-fork block number. Specify the storage slots you want to inspect (comma-separated hex values, e.g., "0x0,0x1,0x2"). The tool will read on-chain data from both blocks and display a preview including: contract address, pre-fork block, post-fork block, bytecode changed status, balance changed status, a list of storage slot diffs (showing old and new values), state trie diff summary, simulated transaction traces, and previous diff records. No transaction is signed or sent—this is a read-only inspection.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to read state at specific block numbers. It fetches bytecode using `provider.getCode(address, blockNumber)`, balances using `provider.getBalance(address, blockNumber)`, and storage slots using `provider.getStorageAt(address, slot, blockNumber)`. The tool compares the values from the pre-fork and post-fork blocks to identify changes. For each storage slot, it displays the old and new values side by side. The bytecode and balance changes are shown as yes/no indicators. The state trie diff is simulated based on the number of storage changes detected. Transaction traces are simulated for demonstration purposes (the tool does not actually execute transaction traces). All reads are performed through the user's connected wallet provider—no centralized APIs are used. The tool does not store any diff results; they are only displayed in the UI.

WHAT IT CANNOT SEE

This tool cannot guarantee that diffs accurately reflect all state changes—it only checks the specified storage slots. It cannot detect if storage slots are read correctly. It cannot verify that transaction traces are complete. It cannot ensure that state trie diffs are accurate. It cannot predict if diffs will be reproducible across different nodes. It cannot validate that the fork endpoint has the necessary archive data. It cannot detect if storage slots have been modified by other transactions not included in the diff. It cannot verify that diffs are comprehensive. It cannot ensure that diffs are comparable across different providers.

PLEASE NOTE

This tool is EVM-only and works across all supported chains (Ethereum, Polygon, BNB Chain, Arbitrum, Optimism, Avalanche). The inspection is performed on the currently connected network; to compare across different chains, you must switch networks and run the inspection separately. The tool does not store or transmit any diff data. Always verify diffs using multiple methods—storage slot values can be interpreted in different ways depending on the contract's implementation.