Ethereum Launches zkAPI for Private AI Payments on Mainnet

Ethereum has launched a private payment system for AI models and metered APIs, called zkAPI, on its mainnet. This system, developed by the Ethereum Foundation and Open Anonymity Project, separates payment credentials from API authentication, reducing the direct link between individual requests and a payer's billing identity.

Users fund a private note in an Ethereum vault, which is then used to generate zero-knowledge proofs showing sufficient funds exist. These proofs are used to create temporary keys with defined spending limits, allowing users to send requests to AI providers without exposing their billing identity.

The system extends beyond individual AI prompts, and is also designed to support AI agents that need to purchase services automatically. This could reduce integration work for developers, as the local client exposes standard OpenAI and Ollama interfaces through localhost.

However, the Ethereum Foundation notes that zkAPI does not provide complete anonymity, as AI providers can still see request content and network information, including an IP address. The system separates payment privacy from network anonymity and content privacy, but remains experimental and will depend on integration by developers and user demand.