Ethereum’s zkAPI brings privacy-preserving API payments to mainnet
zkAPI, built with the Open Anonymity Project, is now live on Ethereum mainnet. It lets users pre-deposit funds in an Ethereum vault and use zero-knowledge proofs to show they have enough credit for API calls without revealing which deposits belong to them. A near-term use case is private AI payments: zkAPI issues short-lived API keys with spending limits, sends prompts directly to the AI provider, and settles usage separately through the payment layer. The release includes a local client, SDK, and browser-based AI chat app. It implements a February concept proposed by Ethereum Foundation researchers and Vitalik Buterin for private, prepaid access to metered APIs. It does not hide prompts or network metadata, so providers may still infer identity across sessions through IP address, timing, or request content.
