Ethereum Mainnet Now Supports Private Metered API Payments

A new payment system has been deployed on Ethereum mainnet, allowing users to make private metered API payments without linking individual requests to a durable billing account. The system, called zkAPI, was built by the Ethereum Foundation's dAI team and the Open Anonymity Project.

zkAPI aims to solve a problem that arises when users pay for metered services such as AI models or cloud APIs. Typically, each payment is tied to the user's identity, allowing providers to build profiles of their customers' behavior over time. This can be problematic for users who ask sensitive questions or engage in activities they'd prefer to keep private.

With zkAPI, users deposit ETH or USDC into a vault contract, which turns that balance into a private 'note' that functions like digital cash. Zero-knowledge proofs then confirm that a payment is valid without revealing the user's identity or what they paid for.