The Ethereum Foundation announced on Thursday that zkAPI has officially launched on the Ethereum mainnet, transitioning an earlier zero-knowledge API payment proposal into a functional implementation for private, prepaid access.
Built in collaboration with the Open Anonymity Project, zkAPI allows users to pay for artificial intelligence and other API services without exposing their billing identities. According to Vittorio Rivabella, AI coordinator at the Ethereum Foundation’s dAI team, users deposit funds into an Ethereum vault and utilize zero-knowledge proofs to demonstrate they possess sufficient credit for API requests, thereby concealing which deposits belong to them.
A primary use case for the system is funding AI usage without tying payments to a specific user. The protocol issues short-lived API keys with established spending limits. While prompts are transmitted directly to the AI provider, usage settlement occurs separately via the payment layer. Additionally, the project has introduced a local client, a software development kit, and a browser-based AI chat implementation.
This mainnet release follows a February proposal by Ethereum co-founder Vitalik Buterin and Ethereum Foundation researcher Davide Crapis regarding zero-knowledge-based API usage credits, successfully bringing the design to life.
The Ethereum Foundation noted that while zkAPI offers private, prepaid access to metered APIs, the system does not conceal prompt contents or network metadata from providers. Consequently, users could potentially be linked across sessions via IP addresses, timing, or details included in their requests.
