Storage Slot Value Diff Tracker

WHAT IT DOES

Storage Slot Value Diff Tracker is a read-only developer tool that tracks changes in contract storage slot values between two block numbers. It reads the contract address, storage slot numbers (user-provided), previous block number, current block number, storage values at specified slots at both blocks, and previous diff records. The tool then compares the values and displays a diff report showing which slots changed, the old and new values, and the total number of changes. This helps developers debug storage changes, verify upgrade behavior, or investigate state inconsistencies.

HOW TO USE

Connect your wallet via the built-in connector. Select the network where the contract is deployed. Enter the contract address, a comma-separated list of storage slot numbers (e.g., "0,1,2,3"), the previous block number, and the current block number. The tool will read storage values at both blocks and display a preview including: contract address, previous block, current block, a list of storage slots with their old and new values (showing only changed slots), and the total number of changes. No transaction is signed or sent—this is a read-only diff tracking.

TECHNICAL MECHANISM

The tool uses ethers.js v5.7.2 to read storage values at specific block numbers. For each slot, it calls `provider.getStorageAt(contractAddress, slotNumber, blockNumber)` twice—once for the previous block and once for the current block. It then compares the two 32-byte values. If they differ, the slot is marked as "changed" and both values are displayed side by side with the old value in red and the new value in green. The tool also counts the total number of changed slots. All reads are performed through the user's connected wallet provider, which must support archive node access for reading historical block states. The tool does not store any diff results; they are only displayed in the UI.

WHAT IT CANNOT SEE

This tool cannot verify that the storage diff is complete—it only checks the slots you provide. It cannot detect if storage slots have changed due to other transactions not reflected in the diff. It cannot guarantee that the diff is accurate—storage reads are subject to the provider's archive node availability. It cannot ensure that the block numbers are valid—you must provide correct block numbers. It cannot validate that the contract state is consistent between the two blocks. It cannot detect if the contract has been modified. It cannot verify that the diff is reproducible. It cannot predict if storage slots will change in future blocks.

PLEASE NOTE

This tool is EVM-only and works across all supported chains (Ethereum, Polygon, BNB Chain, Arbitrum, Optimism, Avalanche). The tool requires archive node access to read storage at historical blocks—some providers may not support this. The inspection is performed on the currently connected network—to track diffs on different chains, you must switch networks. The tool does not store or transmit any diff data. Always interpret storage values with knowledge of the contract's storage layout—the raw values are meaningless without context.