Create a Cryptocurrency-Powered API for Selling Digital Resources with AgentGatePay

Created by

AgentGatePay

Last update

Last update 7 hours ago

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.

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

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:

Click:
Enter:
- AGENTGATEPAY_API_KEY: Your buyer API key
- WALLET_PRIVATE_KEY: Your wallet private key (0x...)
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

Installation (3 minutes)

Step 1: Import Templates

In N8N:

Go to Workflows → Add Workflow
Click ⋮ (three dots) → Import from File
Import all 4 files:
- 🤖 Buyer Agent - CLIENT TEMPLATE.json
- 💲Seller Resource API - CLIENT TEMPLATE.json
- 📊 Buyer Monitoring - AUDIT LOGS.json
- 💲 Seller Monitoring - AUDIT LOGS.json

Step 2: Create Data Table

In N8N Settings:

Go to Settings → Data → Data Tables
Create table: AgentPay_Mandates
Add column: mandate_token (type: String)
Save

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

Open Buyer Agent workflow
Click Execute Workflow
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)

Monitor Activity

Buyer Monitoring

Open: 📊 Buyer Monitoring - AUDIT LOGS

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: 💲 Seller Monitoring - AUDIT LOGS

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

Execute → See:

Total revenue
Commission breakdown
Top payers
Payment count

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:

Ensure your wallet has the selected token on the selected chain
Update Render service to support the chain (add RPC URL)
Gas fees vary by chain:
- Base: ~$0.001 per TX (recommended)
- Polygon: ~$0.01 per TX
- Arbitrum: ~$0.05 per TX
- Ethereum: ~$5-20 per TX (expensive)

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.

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)

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

What's Next?

Learn More

Full Documentation: README.md (comprehensive guide)
API Reference: https://api.agentgatepay.com/docs
Multi-Chain Configuration: See main repository documentation

Advanced Features

Multi-agent orchestration: Multiple buyers → One seller
Dynamic pricing: Adjust prices based on demand
Webhook notifications: Get notified on every payment
Analytics dashboard: https://api.agentgatepay.com/dashboard

Get Help

Email: [email protected]
GitHub: Open an issue in the main repository

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)

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

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