The Ethereum Foundation has collaborated with the Open Anonymous Project to develop zkAPI, which is now running on the Ethereum mainnet. ZkAPI separates payment and identity through zero knowledge proof. After users deposit assets such as ETH and USDC into the vault contract, they can authorize the AI API to use the quota without exposing their identity. The service provider cannot know the payment identity, and the payment service provider cannot associate the consumption with the user. This solution adopts technologies such as Grow16, BN254, Poseidon, and Merkle tree to support users in withdrawing funds from the chain. It is suitable for AI inference, blockchain RPC, and pay as you go scenarios.