Airdrop Eligibility Snapshot Locker

WHAT IT DOES

Airdrop Eligibility Snapshot Locker lets you capture and lock a verifiable snapshot of token holders at a specific block. Instead of relying on off-chain CSV files that can be disputed, you scan the blockchain for all holders of a target token at a given block, apply a minimum balance filter, and deploy a snapshot-locking contract that records the eligibility list on-chain. This creates an immutable, transparent record of who was eligible at the time of the snapshot, which can be used later for airdrop distribution or governance voting. The snapshot hash is stored on-chain, making it tamper-proof and publicly verifiable.

HOW TO USE

Connect your EVM wallet and select the network. Enter the target token address (the token whose holders you want to snapshot) and the snapshot block number. Optionally set a minimum balance threshold to filter out dust accounts. Click "Scan holders" to fetch all holders of the target token at the specified block—the tool scans Transfer events to reconstruct balances and displays the total supply and number of eligible holders. Review the results, then click "Lock snapshot" to deploy a SnapshotLocker contract that records the snapshot hash and holder count on-chain. The contract address and snapshot hash are displayed for verification.

TECHNICAL MECHANISM

The tool reconstructs holder balances at the snapshot block by scanning all Transfer events from block 0 up to the snapshot block using an adaptive chunking strategy—when an RPC endpoint hits a block range limit, the tool halves the chunk size and retries, ensuring the scan completes even on restrictive providers. For each Transfer event, it updates the sender and receiver balances in a local map, filtering out zero-balance addresses and those below the minimum threshold. It then computes the total supply of the target token at the snapshot. The snapshot data (addresses and balances) is hashed using keccak256, and a deployment transaction is submitted to store the hash on-chain in a SnapshotLocker contract. This on-chain record serves as an immutable proof of eligibility for future distribution.

WHAT IT CANNOT SEE

This tool cannot capture holders who have zero balance at the snapshot or who are not represented in Transfer events (e.g., genesis allocations or tokens minted without an accompanying Transfer event). It relies on accurate event data from the target token contract; tokens with transfer fees, rebasing mechanics, or non-standard balance logic (e.g., tokens that update balances in hooks) may produce inaccurate results. The tool does not support tokens with dynamic total supply or tokens that use a different balance accounting method. Gas costs scale with the number of unique holders, which can be significant for tokens with many holders.

PLEASE NOTE

The snapshot block must be in the past and accessible to the RPC provider. The tool uses Transfer events to reconstruct balances, which may be slow for tokens with a long history—use a block number that is not too far in the past for better performance. Once the snapshot is locked on-chain, it cannot be modified. This tool is for EVM chains only and does not support non-EVM networks.