Breaking

Ethereum Foundation and Open Anonymity Project Launch zkAPI for Private, Anonymous API Payments Using Zero-Knowledge Proofs

October 1, 2026 at 20:08 EDT

Foundation Models
Security

The Ethereum Foundation and Open Anonymity Project have introduced zkAPI, a zero-knowledge protocol that enables users to pay for AI APIs and other metered services without revealing their identity or linking payments to specific requests. Live on Ethereum Mainnet as of October 1, 2026, zkAPI represents a significant step toward decoupled payment and usage privacy in the growing AI economy.

Ethereum Foundation • October 2026

Private API Payments via Zero-Knowledge Proofs

zkAPI enables users to pay for AI and metered APIs without linking payment identity to usage.

How zkAPI Works

Payment Layer

User deposits ETH/USDC into vault contract, creates private balance

Proof & Auth

Client generates ZK proof, server issues temporary capped API key

Request Layer

User sends requests directly to API provider using temp key

Privacy Result

Payment server and API provider never see the link between them

Privacy Layers & Limitations

✓ Achieved

Separate payment from request identity
Prevent spend double-linking
Nullifier protects against reuse

⚠ Not Protected

IP address visible to provider
Prompt contents may fingerprint sessions
Writing style and personal details leak

Deployed on Ethereum Mainnet. Supports OpenAI and Ollama-compatible APIs. Designed to scale to RPC, image/video generation, VPNs, and machine-to-machine payments. Marked experimental; users routing through Tor or using VPNs recommended for stronger network privacy.

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