Ethereum Foundation launches zkAPI on mainnet
Ethereum Foundation and Open Anonymity put zkAPI on Ethereum mainnet on Oct. 1, using zero-knowledge proofs to separate AI billing from user identity.
The Blocktape Editors 2 min read c30612
The Ethereum Foundation and Open Anonymity Project launched zkAPI on Ethereum mainnet on Oct. 1, letting users pay for AI and other metered APIs without linking billing identity to requests, according to the Foundation’s announcement.
How does zkAPI separate payment from a request?
Users deposit ETH, USDC or other credits into an Ethereum vault, where their balance becomes a private note. Software on the user’s device creates a zero-knowledge proof that the note can cover a payment without disclosing which deposit funded it.
The zkAPI server checks the proof and issues a short-lived API key with a spending cap. The prompt goes directly to the AI provider with that key; when it expires, the server deducts metered usage from the private balance. One authorization can cover a session rather than requiring a proof for every request.
What can the server and AI provider see?
The server sees that a valid payment exists and the session’s total spending, while the provider sees prompts and responses, the Foundation said. The system is designed to keep the payment link from either party, but it does not hide prompt content from the model provider.
The Foundation said zkAPI also does not provide network anonymity: a stable IP address and request timing can help correlate sessions. Prompt details, writing style or reused conversation history can also link sessions. The Block’s report on the launch likewise notes those limits.
What services can use the system?
AI chat and agents are the first use case. The Foundation also lists blockchain RPC queries, image and video generation, VPN bandwidth and machine-to-machine services as possible applications.
The client exposes standard OpenAI and Ollama APIs locally, the Foundation said, so existing apps can connect through a local gateway. Service providers would need to accept zkAPI proofs and settle signed usage receipts; pricing and rate limits can stay as they are.
Source material
- Foundation’s announcement — blog.ethereum.org
- report on the launch — theblock.co