AgentInvoice

The agentic economy is here. AI agents are making decisions, calling APIs, and completing tasks autonomously. But there's a missing layer: how do agents pay for the data they consume? AgentInvoice is that layer. We built payment middleware that wraps any API and adds per-call micropayments via Circle Nanopayments on Arc. When an AI agent calls a paid endpoint, the middleware intercepts the request, processes a USDC nanopayment on Arc, confirms the transaction on-chain, and returns the response - all in under 5 seconds. The problem: Traditional billing (Stripe, subscriptions) is designed for humans. It requires accounts, credit cards, monthly cycles, and $0.30 minimum fees. None of this works for AI agents making 1,000 API calls per hour at $0.001 per call. What we built: - Payment middleware that intercepts API calls and processes Circle Nanopayments - Three demo paid APIs: weather ($0.001), summarize ($0.005), sentiment ($0.002) - Budget enforcement: middleware blocks payments when agent exceeds spending limit - AI agent demo: Grok autonomously decides what data it needs, pays for it, and completes tasks end-to-end The demo shows Grok receiving a task, calling three paid APIs, paying for each autonomously, hitting a budget wall on a complex task, getting blocked by the middleware, and adapting - all without human involvement. Every payment is verified on Arc Block Explorer. Why this matters for Arc: every API call equals one Arc transaction. 1,000 developers × 10,000 calls/day = 10 million transactions/day on Arc. AgentInvoice is the developer onboarding ramp and transaction volume engine for the agentic economy. Tech stack: Node.js, Express, Circle App Kit, @circle-fin/adapter-viem-v2, Viem, Grok API (xAI), Arc Testnet.