Airdrop Eligibility Turns Wallet History Into a Score

Airdrop eligibility is calculated by scoring wallet activity before a fixed snapshot and then excluding suspected bots: on March 16, 2023, Arbitrum disclosed that 625,143 wallets qualified, about 28% of the roughly 2.3 million addresses that had bridged to Arbitrum One through February 6, according to its distribution analysis with Nansen. That observed result shows what eligibility measures well—transactions, value and time—and what it cannot establish: whether one address represents one human.

How does an airdrop score a wallet?

A project reconstructs each address’s history from blocks, transaction receipts and contract events, converts selected actions into features, and applies thresholds or points. A holder snapshot asks only what an address owned at one block; a behavior-based model can distinguish a one-day deposit from months of recurring use.

• Timing: Was the action completed before the snapshot block?
• Depth: How much value, liquidity or voting power was committed?
• Duration: Did activity span several weeks or months?
• Breadth: Did the wallet use multiple contracts, chains or protocol functions?

The event being counted matters. An ERC-20 approval authorizes a contract to spend tokens but does not prove that a later deposit occurred; Manta Pacific’s ERC-20 deposit approval flow illustrates why an indexer must separate permission from execution. Counting both as deposits would inflate a wallet’s score.

Why can an active wallet still be ineligible?

An active wallet can fail because eligibility is a classification decision, not a complete record of economic contribution. Arbitrum awarded points for bridging, transaction frequency, activity over time, transferred value and Nova usage, while requiring at least three points. It also deducted points for patterns associated with Sybil farming.

Filters commonly cluster addresses funded by the same source, moving identical amounts at similar times or converging on one exchange deposit address. Those signals reduce mass farming, but they can also group legitimate users, payroll recipients or managed accounts. Conversely, a skilled operator can vary timing and funding paths. The unresolved gap is identity: public ledgers expose relationships between transactions, not definitive ownership of wallets.

What does eligibility calculation change for operators?

For operators, transparent scoring enables an auditable distribution but creates infrastructure and economic costs. Teams need reliable archive access, decoded contract events, cross-chain reconciliation and reproducible queries at an exact block height. RPC providers and indexers absorb the historical scan; sequencers and validators see a shorter burst when users generate qualifying activity or submit claims.

The clear operating rule is to publish criteria, snapshot blocks, exclusions and the final allocation root whenever gaming risk permits. Hidden weights may slow farmers, but they also prevent independent reproduction and turn false positives into unresolvable support disputes. Users should not assume today’s transaction count predicts a future allocation: weights, identity checks and token supply remain project choices, and an eligibility score says nothing certain about market value.

The next measurable event for any campaign is publication of its snapshot block and recipient set. Comparing eligible addresses, excluded clusters and eventual claim rate will show whether the model rewarded sustained use or merely shifted farming into harder-to-detect patterns.