The Ethereum Foundation announced on Thursday that zkAPI, a system built with the Open Anonymity Project to let users pay for AI and other API services without revealing their billing identities, has gone live on Ethereum mainnet.
Users deposit funds into an Ethereum vault, then use zero-knowledge proofs to prove they have enough credit to pay for API requests without revealing which deposits are theirs, according to a post from Vittorio Rivabella, AI coordinator at the Ethereum Foundations dAI team.
One of the immediate use cases of the system is paying for the use of AI without linking the payment to a user. zkAPI issues short-lived API keys with predefined spending limits. Prompts are sent directly to the AI provider, while usage is settled separately through the payment layer. The project has also released a local client and software development kit, along with a browser-based AI chat implementation.
The launch follows a February proposal by Ethereum Foundation researcher Davide Crapis and Ethereum co-founder Vitalik Buterin for ZK-based API usage credits. The new release turns that design into a working mainnet implementation.
The concept was presented as a way to give users private, prepaid access to AI and other metered APIs. However, zkAPI does not hide prompt contents or network metadata from providers, meaning users can still potentially be linked across sessions through IP addresses, timing or information contained in their requests.