The Ethereum Foundation and Open Anonymity Project launched zkAPI on Oct. 1 on Ethereum mainnet, allowing users to deposit ETH, USDC or other supported assets into an onchain vault and pay for AI requests without directly revealing the funding identity. User devices generate zero-knowledge proofs showing that a private note has sufficient unspent funds; zkAPI then issues a short-lived API key with a dollar cap. The provider receives the prompt but not the billing identity, while the payment server does not see the content. Signed usage receipts let the system deduct actual consumption rather than the full cap. The design does not hide prompts, IP addresses, timing patterns or other identifying clues, and the project remains experimental. Its rules also allow an expired active note's full deposit to go to the treasury, while pending withdrawals are exempt and an owner pause can block new exits.