Ethereum Foundation Launches zkAPI for Private AI Model Payments

The Ethereum Foundation has launched zkAPI, a system that enables users to pay for AI models and other pay-per-use APIs without revealing their identity. The system was developed in collaboration with the Open Anonymity Project and is now live on the Ethereum mainnet. Users first deposit ETH or USDC into a treasury, then use zero-knowledge proofs to obtain temporary keys with usage credits to invoke models, decoupling payment from authentication within the API flow.

The system was co-designed by Vitalik Buterin and is based on a design publicly released in February. According to the Ethereum Foundation, each AI API call today carries an identity, and the service provider can piece together a user's usage history over the years into a single profile. zkAPI abstracts away payments, making it a generalization of the unlinkable reasoning of the Open Anonymity Project.

According to the Ethereum Foundation, the zkAPI system does not provide network-layer anonymity. The gateway may correlate requests coming from a fixed IP address, and users requiring stronger privacy should route traffic through Tor. The session may also be reassociated through prompt content, and the GitHub repository for the zkAPI project describes this protocol as experimental.