Ethereum's zkAPI Enables Private Payments for AI Services

The Ethereum Foundation and Open Anonymity Project have collaborated to launch zkAPI, a system designed to allow users to pay for AI services without linking their requests to a permanent billing identity.

This innovative tool uses zero-knowledge proofs to separate payment authorization from the conversation itself. The provider sees the requests, while the payment layer sees only the spend.

The user funds an Ethereum vault and generates a proof showing sufficient funds are available without identifying the deposit. A unique spending marker prevents reusing the same spending state for another authorization.

The server issues a temporary API key with a spending limit, and the writing application uses it to contact the AI service directly. The payment proofs and accounting operate off-chain, reducing Ethereum transactions involved in funding or closing the balance.