Snapshot Block
A specific, predetermined block height used as the reference point for determining who held which assets, used to fairly distribute an airdrop or weight an off-chain governance vote.
A snapshot block is a specific, predetermined block height designated as the exact reference point for recording who held which assets and in what quantity at that precise moment in the blockchain's history. Projects commonly use a snapshot block to determine airdrop (see Kaavon's "Airdrop" glossary definition) eligibility and allocation sizes, or as the basis for weighting votes in an off-chain governance system like Snapshot voting (see Kaavon's "Snapshot Voting" glossary definition), which derives its name directly from this mechanism.
Using a fixed, predetermined snapshot block rather than a live, real-time balance prevents gaming strategies like temporarily borrowing a large token balance from a flash loan right before a close-to-real-time check — since the snapshot locks in a specific historical moment that already occurred and can't be altered retroactively. The exact snapshot block is sometimes announced publicly in advance, and sometimes deliberately kept undisclosed until after it has already passed, specifically to prevent last-minute balance manipulation aimed at maximizing eligibility.
Examples
- A project airdropping tokens to early users might take a snapshot at a specific block height, basing each wallet's allocation on its token balance at that exact historical moment.
- Projects sometimes keep the exact snapshot block undisclosed until after it has passed, specifically to prevent users from temporarily inflating their balance right before it to maximize their allocation.