The Ethereum Foundation launches zkAPI, supporting anonymous AI API payments.

According to official announcements, the Ethereum Foundation has partnered with the Open Anonymity Project to develop zkAPI, which is now live on the Ethereum mainnet. zkAPI leverages zero-knowledge proofs to separate payments from identities: users only need to deposit assets like ETH and USDC into an Ethereum vault contract once, then authorize AI API usage without exposing their personal identity. Service providers can view request content but cannot access the payer’s identity; payment processors only see the amount spent, with no way to link it to specific requests or individual users. The zkAPI workflow operates as follows: user devices generate proofs verifying that funds are sufficient for the transaction and have not been previously spent. Servers validate these proofs to issue temporary API keys with usage limits and expiration periods. Users then send requests directly to AI service providers using these keys, which record actual usage and generate signed credentials. The system ultimately deducts fees from the user’s private balance based on real consumption. The Ethereum network only logs on-chain operations such as deposits, settlements, and withdrawals, with no insight into which services the funds are allocated to. The solution employs cryptographic technologies including Groth16, BN254, Poseidon, and Merkle trees, and allows users to withdraw funds directly from the blockchain if the server ceases operation. The Ethereum Foundation noted that zkAPI is initially targeted at AI inference scenarios, as user prompts submitted to AI models may involve sensitive information like health and financial data. However, the mechanism can also be applied to pay-as-you-go use cases such as blockchain RPC, image generation, and video generation.