Ethereum Unveils zkAPI for Private AI Payments on Mainnet

The Ethereum Foundation and Open Anonymity Project have launched zkAPI on the Ethereum mainnet. This protocol allows users to pay for AI inference without linking individual requests to their wallet.

ZkAPI uses private prepaid credits instead of persistent billing identities, giving users unlinkable payments. This is achieved through zero-knowledge proofs that authorize spending without exposing which deposit is being spent.

The system's design was published in February by Ethereum researcher Davide Crapis and co-founder Vitalik Buterin. The Open Anonymity Project developed the client, server, and smart contracts running on mainnet.

A user first deposits credits into an Ethereum vault, which becomes a private note represented through a cryptographic commitment. When accessing AI services, software generates a proof that a valid note has sufficient funds without identifying the original deposit.