The Ethereum Foundation and the Open Anonymity Project have unveiled zkAPI, a system for paying for API requests privately using zero-knowledge proofs. The first demo of the technology is already live in OA Chat, a browser-based AI chat where users can pay for usage without each request being tied to an account.
Using a paid AI service almost always links three things: an API key, an account and a payment method. zkAPI tries to separate them. The user tops up a shared balance in credits and then proves the right to limited usage with a cryptographic proof, without revealing their payment history to the service provider.
How zkAPI works
- the user deposits credits into a smart contract once;
- each use generates a proof of the right to pay;
- the service sees an authorized request, and the payment layer sees a charge;
- these two parts shouldn’t get a shared link showing who exactly sent a given request.
The approach is interesting beyond chatbots. In theory it could work for any metered API: text translation, image generation, data analysis or cloud tools. But for now it’s early infrastructure, not a universal replacement for familiar subscriptions.
What OA Chat is for
OA Chat is a clear example of zkAPI in use. It runs in the browser and shows what access to AI could look like without a traditional account with a payment intermediary. Still, users need to understand crypto wallets, the Ethereum network and transaction fees, which limits mass adoption at the start.
FAQ
What is a zero-knowledge proof?
It’s a way to prove a right or a fact without revealing unnecessary underlying data.
Does zkAPI hide the request text from the model?
No. The service still needs the request itself to answer it. The technology separates payment from usage history.
Do you need crypto to use OA Chat?
The current setup uses credits on the Ethereum network, so you’ll need to understand basic wallet operations to use it.
