x402 Tax Compliance

The x402 tax gap

3-step integration

x402 payment middleware

Add tax calculation between the HTTP 402 response and the payment settlement. One API call per transaction.

// x402 payment middleware with tax compliance
import { AgentTax } from "@agenttax/sdk";

const tax = new AgentTax({ apiKey: "atx_live_..." });

async function handleX402Payment(resourceUrl, paymentDetails) {
  // 1. Determine the tax obligation
  const taxResult = await tax.calculate({
    role: "buyer",
    amount: paymentDetails.amount,
    buyer_state: paymentDetails.buyerState,
    transaction_type: "compute",  // or "api_access", "data_purchase"
    counterparty_id: paymentDetails.sellerAddress,
    buyer_zip: paymentDetails.buyerZip,   // optional — for local rates
  });

  // 2. Total cost = resource price + applicable tax
  const totalCost = paymentDetails.amount + taxResult.sales_tax.amount;

  // 3. Settle via x402 (USDC on Base)
  const receipt = await settleX402Payment(resourceUrl, totalCost);

  // 4. Record for compliance
  console.log("Tax:", taxResult.sales_tax.amount);
  console.log("Rate:", taxResult.sales_tax.combined_rate * 100, "%");
  console.log("Jurisdiction:", taxResult.sales_tax.buyer_state);
  console.log("Transaction ID:", taxResult.transaction_id);

  return { receipt, tax: taxResult };
}

Python example

Using the AgentTax Python SDK for x402 payment flows.

from agenttax import AgentTaxClient

client = AgentTaxClient(api_key="atx_live_...")

# Before settling an x402 payment
tax = client.calculate(
    role="buyer",
    amount=100.00,
    buyer_state="TX",
    transaction_type="compute",
    counterparty_id="0x1234...seller",
)

total_cost = 100.00 + tax["sales_tax"]["amount"]
print(f"Resource: $100, Tax: {tax['sales_tax']['amount']:.2f}, Total: {total_cost:.2f}")

Response shape

{
  "success": true,
  "sales_tax": {
    "taxable": true,
    "amount": 5.00,
    "state_tax": 5.00,
    "local_tax": 0.00,
    "combined_rate": 0.05,
    "buyer_state": "TX",
    "classification_basis": "digital_service",
    "advisories": [
      "TX §151.351: 80% of digital services taxable (20% statutory exemption)"
    ]
  },
  "confidence": { "score": 95, "level": "high" },
  "transaction_id": "txn_x402_abc123"
}

Using PayAI as your x402 facilitator? See the PayAI-specific integration guide.