Create a cryptocurrency-powered API for selling resources with AgentGatePay

AgentGatePay N8N Quick Start Guide

Get your AI agents paying for resources autonomously in under 10 minutes.

> ⚠️ BETA VERSION: These templates are currently in beta. We're actively adding features and improvements based on user feedback. Expect updates for enhanced functionality, additional blockchain networks, and new payment options.

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What You'll Build

• Buyer Agent: Automatically pays for API resources using USDC, USDT, or DAI on Ethereum, Base, Polygon, or Arbitrum blockchains
• Seller API: Accepts multi-token payments and delivers resources
• Monitoring: Track spending and revenue in real-time across all chains and tokens

Supported Tokens:

• USDC (6 decimals) - Recommended
• USDT (6 decimals)
• DAI (18 decimals)

Supported Blockchains:

• Ethereum (mainnet)
• Base (recommended for low gas fees ~$0.001)
• Polygon
• Arbitrum

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Prerequisites (5 minutes)

1. Create AgentGatePay Accounts

Buyer Account (agent that pays):

curl -X POST https://api.agentgatepay.com/v1/users/signup \
  -H "Content-Type: application/json" \
  -d '{
    "email": "[email protected]",
    "password": "SecurePass123!",
    "user_type": "agent"
  }'

Seller Account (receives payments):

curl -X POST https://api.agentgatepay.com/v1/users/signup \
  -H "Content-Type: application/json" \
  -d '{
    "email": "[email protected]",
    "password": "SecurePass123!",
    "user_type": "merchant"
  }'

Save both API keys - shown only once!

2. Deploy Transaction Signing Service (2 minutes)

One-Click Render Deploy:

1. Click:
2. Enter:
   • AGENTGATEPAY_API_KEY: Your buyer API key
   • WALLET_PRIVATE_KEY: Your wallet private key (0x...)
3. Deploy → Copy service URL: https://your-app.onrender.com

3. Fund Wallet

• Send USDC, USDT, or DAI to your buyer wallet
• Default: Base network (lowest gas fees)
• Need ~$1 in tokens for testing + ~$0.01 ETH for gas (on Ethereum) or ~$0.001 on Base

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Installation (3 minutes)

Step 1: Import Templates

In N8N:

1. Go to Workflows → Add Workflow
2. Click ⋮ (three dots) → Import from File
3. Import all 3 workflows:
   • 🤖 Create a Cryptocurrency-Powered API for Selling Digital Resources with AgentGatePay
   • 💲Create a Cryptocurrency-Powered API for Selling Digital Resources with AgentGatePay
   • 📊 AgentGatePay - Monitoring Dashboard

Step 2: Create Data Table

In N8N Settings:

1. Go to Settings → Data → Data Tables
2. Create table: AgentPay_Mandates
3. Add column: mandate_token (type: String)
4. Save

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Configuration (2 minutes)

Configure Seller API First

Open: 💲Seller Resource API - CLIENT TEMPLATE

Edit Node 1 (Parse Request):

const SELLER_CONFIG = {
  merchant: {
    wallet_address: "0xYourSellerWallet...",  // ← Your seller wallet
    api_key: "pk_live_xyz789..."              // ← Your seller API key
  },
  catalog: {
    "demo-resource": {
      id: "demo-resource",
      price_usd: 0.01,                        // $0.01 per resource
      description: "Demo API Resource"
    }
  }
};

Activate workflow → Copy webhook URL

Configure Buyer Agent

Open: 🤖 Buyer Agent - CLIENT TEMPLATE

Edit Node 1 (Load Config):

const CONFIG = {
  buyer: {
    email: "[email protected]",              // ← Your buyer email
    api_key: "pk_live_abc123...",            // ← Your buyer API key
    budget_usd: 100,                         // $100 mandate budget
    mandate_ttl_days: 7                      // 7-day validity
  },
  seller: {
    api_url: "https://YOUR-N8N.app.n8n.cloud/webhook/YOUR-WEBHOOK-ID"  // ← Seller webhook base URL ONLY (see README.md for extraction instructions)
  },
  render: {
    service_url: "https://your-app.onrender.com"  // ← Your Render URL
  }
};

---

Run Your First Payment (1 minute)

Execute Buyer Agent

1. Open Buyer Agent workflow
2. Click Execute Workflow
3. Watch the magic happen:
   • Mandate created ($100 budget)
   • Resource requested (402 Payment Required)
   • Payment signed (2 transactions: merchant + commission)
   • Payment verified on blockchain
   • Resource delivered

Total time: ~5-8 seconds

Verify on Blockchain

Check transactions on BaseScan:

https://basescan.org/address/YOUR_BUYER_WALLET

You'll see:

• TX 1: Commission to AgentGatePay (0.5% = $0.00005)
• TX 2: Payment to seller (99.5% = $0.00995)

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Monitor Activity - Choose Buyer/Seller or both

Buyer Monitoring

Open: 📊 AgentGatePay - Monitoring Dashboard

Edit Node 1: Set your buyer wallet address and API key

Execute → See:

• Mandate budget remaining
• Payment history
• Total spent
• Average transaction size

Seller Monitoring

Open: 📊 AgentGatePay - Monitoring Dashboard

Edit Node 1: Set your seller wallet address and API key

Execute → See:

• Total revenue
• Commission breakdown
• Top payers
• Payment count

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How It Works

Payment Flow

1. Buyer Agent requests resource
   ↓
2. Seller returns 402 Payment Required
   (includes: wallet address, price, token, chain)
   ↓
3. Buyer signs TWO blockchain transactions via Render:
   - Merchant payment (99.5%)
   - Gateway commission (0.5%)
   ↓
4. Buyer resubmits request with transaction hashes
   ↓
5. Seller verifies payment with AgentGatePay API
   ↓
6. Seller delivers resource

Key Concepts

AP2 Mandate:

• Pre-authorized spending authority
• Budget limit ($100 in example)
• Time limit (7 days in example)
• Stored in N8N Data Table for reuse

x402 Protocol:

• HTTP 402 "Payment Required" status code
• Seller specifies payment details
• Buyer pays and retries with proof

Two-Transaction Model:

• Transaction 1: Merchant receives 99.5%
• Transaction 2: Gateway receives 0.5%
• Both verified on blockchain

---

Customization

Change Resource Price

Edit seller Node 1:

catalog: {
  "expensive-api": {
    id: "expensive-api",
    price_usd: 1.00,  // ← Change price
    description: "Premium API access"
  }
}

Add More Resources

catalog: {
  "basic": { id: "basic", price_usd: 0.01, description: "Basic API" },
  "pro": { id: "pro", price_usd: 0.10, description: "Pro API" },
  "enterprise": { id: "enterprise", price_usd: 1.00, description: "Enterprise API" }
}

Buyer requests by ID: ?resource_id=pro

Change Blockchain and Token

By default, templates use Base + USDC. To change:

Edit buyer Node 1 (Load Config):

const CONFIG = {
  buyer: { /* ... */ },
  seller: { /* ... */ },
  render: { /* ... */ },
  payment: {
    chain: "polygon",  // Options: ethereum, base, polygon, arbitrum
    token: "DAI"       // Options: USDC, USDT, DAI
  }
};

Important:

1. Ensure your wallet has the selected token on the selected chain
2. Update Render service to support the chain (add RPC URL)
3. Gas fees vary by chain.

Token Decimals:

• USDC/USDT: 6 decimals (automatic conversion)
• DAI: 18 decimals (automatic conversion)

Schedule Monitoring

Replace "Execute Workflow" trigger with Schedule Trigger:

• Buyer monitoring: Every 1 hour
• Seller monitoring: Every 6 hours

Add Slack/Email node to send alerts.

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Troubleshooting

"Mandate expired"

Fix: Delete mandate from Data Table → Re-execute workflow

"Transaction not found"

Fix: Wait 10-15 seconds for blockchain confirmation → Retry

"Render service unavailable"

Fix: Render free tier spins down after 15 min → First request takes ~5 sec (cold start)

"Insufficient funds"

Fix: Send more tokens (USDC/USDT/DAI) to buyer wallet

• Check balance on blockchain explorer (BaseScan for Base, Etherscan for Ethereum, etc.)

"Webhook not responding"

Fix: Ensure seller workflow is Active (toggle in top-right)

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Production Checklist

Before going live:

• Use separate wallet for agent (not your main wallet)
• Set conservative mandate budgets ($10-100)
• Monitor spending daily (use monitoring workflows)
• Upgrade Render to paid tier ($7/mo) for no cold starts
• Set up Slack/email alerts for low balance
• Test with small amounts first ($0.01-0.10)
• Keep API keys secure (use N8N credentials manager)
• Review transactions on blockchain explorer weekly

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Summary

You just built:

• Autonomous payment agent (buys resources automatically)
• Monetized API (sells resources for USDC, USDT, or DAI)
• Multi-chain support (Ethereum, Base, Polygon, Arbitrum)
• Real blockchain transactions (verified on-chain)
• Budget management (AP2 mandates)
• Monitoring dashboard (track spending/revenue)

Total setup time: ~10 minutes Total cost: $0 (Render free tier + AgentGatePay free)

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Ready to scale? Connect multiple agents, add more resources, integrate with your existing systems!

Questions? Check README.md or contact [email protected]

Website: https://www.agentgatepay.com