◢ AgentPay

The drop-in payment rail for AI agents — open source.

Let autonomous agents pay your API in USDC over the open x402 standard, with one line of code. Non-custodial: money settles straight to your wallet. AgentPay never touches it.

Quickstart · How it works · The agent side · Self-host · Security

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AI agents are starting to buy things: APIs, data, compute, actions. AgentPay is the easiest way to charge them. Drop one line into your server, and an unpaid request gets an HTTP 402 with a payment requirement; the agent pays USDC and retries; the money lands in your wallet. Think Stripe, but for agents, and you hold the keys.

It's not a new rail. It rides the open x402 standard and settles in USDC on Base, and gives merchants the nicest possible way to accept agent payments: a drop-in SDK, a dashboard, a CLI for coding agents, and a Stripe-style button.

Quickstart (60 seconds)

npm i @agentpay/merchant-sdk

Pre-release: the npm package is publishing shortly. Until then, clone this repo and run pnpm build:sdk — the SDK lives in packages/merchant-sdk.

// Gate any route behind an agent payment. That's the whole integration.
import { paymentGateway } from "@agentpay/merchant-sdk/express";

app.use("/api/premium", paymentGateway({ payTo: "0xYourWallet", amount: 0.5 }));

Deploy as usual. Unpaid agents get a 402; paid agents stream USDC to your wallet. Works the same on Next.js (withPayment) and any Fetch server — Hono, Bun, Deno (createWebGateway).

How it works

sequenceDiagram
    participant A as AI Agent
    participant M as Your Server
    participant C as Base / USDC
    A->>M: GET /api/premium
    M-->>A: 402 Payment Required (payTo, amount)
    A->>C: transfer USDC to your wallet
    C-->>A: tx hash
    A->>M: GET /api/premium (X-PAYMENT signed proof)
    M->>C: verify on-chain (amount, payer, confirmations)
    M-->>A: 200 OK + content

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The agent's proof is signed by the paying wallet and verified against the on-chain payer, so a leaked transaction hash is useless to anyone else. Each payment unlocks a resource once.

Why AgentPay

• One-line integration. paymentGateway({ payTo, amount }). No accounts, no merchant onboarding, no SDK ceremony.
• Non-custodial. USDC settles wallet-to-wallet. AgentPay never holds funds or private keys. Final settlement, no chargebacks.
• Agent-native. The agent side is autonomous: a drop-in fetch that pays any 402 and retries, plus an LLM tool for OpenAI / LangChain / CrewAI / OpenClaw.
• Hardened. Signed proofs bound to payer + amount + resource, on-chain verification, reorg confirmations, durable replay protection, rate limiting, and Sign-In-With-Ethereum hardened against takeover. See SECURITY.md.
• Coding-agent friendly. A coding agent can provision projects, keys, and wallets itself via the CLI/API with an admin token — no GUI. See AGENTS.md.
• Self-host in one command. Your infra, your wallet, your keys. Or run the dashboard locally to watch the money land.
• Open standard. x402-compatible and USDC, so you're not locked into us.

The agent side

Give an agent a funded wallet and it pays for what it needs, on its own:

import { createPaidFetch } from "@agentpay/merchant-sdk/client";

const fetch = createPaidFetch({ privateKey: process.env.AGENT_KEY, dailyLimitUsdc: 10 });
await fetch("https://api.you.com/api/premium"); // any 402 is paid + retried automatically

Spend policy + budget. Pre-authorize what an agent may pay — exact vendors, blocked sites, intent-based per-payment caps, a model allow-list, and a daily limit — all enforced before every payment via a policy. Gasless (EIP-3009): with gasless: true the agent signs a USDC authorization (no ETH) and the merchant gateway settles it on-chain.

Agent owners get a dashboard at /wallet to create + fund an agent, set its policy, and export a ready-to-install OpenClaw skill.

Or hand it to an LLM as a tool:

import { agentPaymentTool } from "@agentpay/merchant-sdk/client";

const tool = agentPaymentTool({ privateKey: process.env.AGENT_KEY });
// OpenAI tool-calling: tools: [tool.toOpenAITool()] → route calls to tool.invoke(args)

Drop-in button & payment links

For humans, add a USDC pay or subscribe button to any page — no framework, one line:

<script src="https://your-host/agentpay-button.js"></script>
<agentpay-button to="0xYourWallet" amount="5"></agentpay-button>

Or share a hosted payment link — every project gets a checkout page at /pay/<projectId>, with a Preview button in the dashboard.

The dashboard

Run the dashboard, connect the wallet you set as payTo, and one click signs you in (the session persists, so you don't re-login). Every payment your gateway accepts shows up with your live USDC balance — it reads the chain directly. Create projects and API keys, register paying agents with per-agent spend caps, set HMAC-signed webhooks, and manage it all (rotate keys, edit, delete).

Self-host

cp .env.example .env          # set SESSION_SECRET (>=32 chars) and AGENTPAY_PAYTO
docker compose up --build     # dashboard on http://localhost:3000

A multi-stage build compiles the SDK, builds the dashboard as a standalone Next.js server, and ships only that. Config is runtime env, so the same image runs anywhere. Nothing leaves your box; no funds are ever custodied.

Local dev:

pnpm install
cp apps/dashboard/.env.example apps/dashboard/.env.local   # set SESSION_SECRET
pnpm build:sdk && pnpm dev    # dashboard on http://localhost:3000

Network: Base Sepolia testnet, USDC (0x036CbD53842c5426634e7929541eC2318f3dCF7e). No real funds while you build.

See the whole loop

AGENT_PRIVATE_KEY=0x… TARGET_URL=http://localhost:3000/api/premium pnpm demo

Pays the 402, prints the tx, retries, and gets the content: 402 → pay → sign → 200. With no key it generates a throwaway wallet and tells you how to fund it (Base Sepolia USDC from faucet.circle.com + a little ETH).

Tested & hardened

48 tests across the merchant SDK and dashboard: payment verification (amount, recipient, USDC contract, reorg confirmations, freshness, signature binding), the full 402 → pay → sign → 200 integration loop, replay/underpayment/stolen-proof rejection, webhook HMAC integrity, input validation, and rate limiting. The codebase has been through an adversarial security review — threat model and findings in SECURITY.md.

pnpm -r test

Project layout

agentpay/
  packages/merchant-sdk/   # x402 TypeScript SDK: gateway (express/next/web), agent payer (client), verify, proof
  apps/dashboard/          # Next.js dashboard: SIWE auth, control plane, payment links, drop-in button
  scripts/                 # agentpay CLI + the end-to-end demo
  examples/                # runnable merchant + agent demos

Roadmap

• EIP-3009 gasless settlement — wired as opt-in (gasless: true + gateway settle); next: make it the default flow
• On-chain spend-limit policy contract — non-bypassable vendor caps / allowances (the policy is enforced agent-side today)
• Mainnet (Base, then more chains)
• Persistent + multi-instance backends (Redis), hosted option
• npm publish of @agentpay/merchant-sdk

Contributing

Issues and PRs are welcome — this is built in the open. Good first areas: framework adapters, more agent-framework tool bindings, and the roadmap items above. Run pnpm -r test before opening a PR.

If AgentPay is useful to you, ⭐ star the repo — it genuinely helps others find it.

License

MIT. Use it, fork it, ship it.

Built by Citerlabs.