zkAPI launches private prepaid API payments on Ethereum mainnet

zkAPI has launched on Ethereum mainnet, turning an earlier proposal for private, prepaid API access into a working implementation. The Open Anonymity Project built zkAPI with the Ethereum Foundation. The system uses zero-knowledge proofs to separate API payments from user identities. According to Ethereum Foundation dAI team AI coordinator Vittorio Rivabella, users can pay for metered API access without being identified. Users deposit funds into an Ethereum vault and prove they have enough credit for API requests without revealing which deposits are theirs. One immediate use case is paying for AI services without linking the payment to a user. zkAPI issues short-lived API keys with predefined spending limits. Users send prompts directly to the AI provider, while a separate payment layer settles usage. The project has released a local client, a software development kit and a browser-based AI chat implementation. The launch follows a February proposal for zero-knowledge-based API usage credits by Ethereum Foundation researcher Davide Crapis and Ethereum co-founder Vitalik Buterin. The proposal envisioned private, prepaid access to AI and other metered APIs. However, zkAPI does not hide prompt contents or network metadata from providers. Providers could potentially link users across sessions through IP addresses, timing or information in their requests.