Ethereum Foundation Launches zkAPI for Private AI Model Payments

The Ethereum Foundation has launched zkAPI, a system for privacy-preserving AI model payments. The system was developed in collaboration with the Open Anonymity Project, an open-source AI privacy project, and is now live on the Ethereum mainnet.

Users first deposit tokens such as ETH or USDC into a vault contract, which records the user's balance as a private note. When spending these tokens, software on the user's device generates a zero-knowledge proof demonstrating that the request is backed by a sufficiently funded note, without revealing which specific note is used or the corresponding deposit details.

The zkAPI system allows users to pay for AI models and other pay-per-use APIs without revealing their identity. This adds value to narratives around ETH as a settlement layer and AI agent micropayments. However, the protocol remains labeled as experimental, and gateways may still link requests via IP.

The system was co-designed by Vitalik Buterin and implements the 'ZK API Usage Credits' design published by Davide Crapis and Ethereum co-founder Vitalik Buterin on the Ethereum Research forum in February. Crapis leads the dAI team at the Ethereum Foundation, which aims to enhance Ethereum's capabilities as an AI settlement and coordination layer.