Ethereum Foundation launches zkAPI to enable anonymous AI API payments

BlockBeats news, October 2nd, according to official sources, the Ethereum Foundation announced a joint development of zkAPI with the Open Anonymity Project, which is already running on the Ethereum mainnet. zkAPI separates payment from identity through zero-knowledge proofs. Users only need to deposit assets such as ETH and USDC into a vault contract on Ethereum once, and can then authorize AI API usage quotas without revealing their identity. Service providers can see the request content but cannot know the payment identity; payment service providers can only see the consumption amount and cannot associate it with specific requests or users.

The operating mechanism of zkAPI is that the user's device generates a proof verifying that a certain amount of funds is sufficient to cover the current consumption and has not been used before. After the server verifies it, a temporary API key with a quota limit and validity period is generated. The user can then directly use this key to send requests to the AI service provider. The service provider records the actual usage and generates a signed credential. The system ultimately deducts the fee from the user's private balance according to actual usage. The Ethereum network only records on-chain operations such as deposits, settlements, and withdrawals, and cannot know which services the specific funds are used to pay for. This solution uses cryptographic technologies such as Groth16, BN254, Poseidon, and Merkle trees, and allows users to withdraw funds directly from the chain even if the server stops running.

The Ethereum Foundation stated that zkAPI is initially aimed at AI inference scenarios, because the prompts users submit to AI models may involve sensitive information such as health and finance, but this mechanism can also be used for pay-per-use scenarios such as blockchain RPC, image and video generation.