Base Build launches Verify Onchain to curb Sybil attacks in airdrops

Base Build has introduced Base Verify Onchain, a new identity-verification tool aimed at tackling Sybil attacks across blockchain applications. The feature is now live on the Base Sepolia testnet and lets developers enforce rules such as one claim per real user directly in smart contracts. According to Base Build, conventional airdrop systems are often exploited by large batches of wallets controlled by professional airdrop farmers, leaving users who actually helped build products with limited rewards. Verify Onchain addresses that issue by creating a stable identity hash for each real user, allowing projects to detect multiple wallets tied to the same person without collecting private data such as names or account details. Users can verify themselves with existing accounts including Coinbase, Instagram, X and TikTok. The system then returns a verified identity credential to the smart contract, which can automatically apply claim caps, voting limits or allocation controls. Base Build said Base Verify has already been used more than 300,000 times and is serving projects including Base App, Cody, Scratch and Bracket.