Tax compliance for PayAI Network merchants

PayAI settles x402 payments for 1,000+ merchants across Base, Polygon, Avalanche, Sei, X Layer, and Solana. Every one of those transactions is a taxable event in the US. AgentTax is the drop-in layer that records tax obligations per-jurisdiction on every settlement — so when you file, the 1099-DA data is already structured and your state DOR exposure is known.

How it works

The handler

PayAI's @x402/express middleware handles settlement. Your route handler records the tax obligation to AgentTax right after. One fetch, one transaction_id returned, logged per-jurisdiction.

// PayAI x402 merchant — record each settled transaction to AgentTax.
// Drops into the route handler that runs AFTER successful x402 settlement.
import express from "express";
import { paymentMiddleware, x402ResourceServer } from "@x402/express";
import { ExactEvmScheme } from "@x402/evm/exact/server";
import { HTTPFacilitatorClient } from "@x402/core/server";
import { facilitator } from "@payai/facilitator";

const app = express();
const facilitatorClient = new HTTPFacilitatorClient(facilitator);

app.use(paymentMiddleware(
  {
    "GET /weather": {
      accepts: [{
        scheme: "exact", price: "$0.001",
        network: "eip155:8453", payTo: process.env.EVM_ADDRESS,
      }],
      description: "Weather data",
      mimeType: "application/json",
    },
  },
  new x402ResourceServer(facilitatorClient)
    .register("eip155:8453", new ExactEvmScheme()),
));

async function recordTax({ amount, buyerState, counterpartyId }) {
  const res = await fetch("https://agenttax.io/api/v1/calculate", {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Authorization": `Bearer ${process.env.AGENTTAX_API_KEY}`,
    },
    body: JSON.stringify({
      role: "seller",
      amount,
      buyer_state: buyerState,
      transaction_type: "compute",
      counterparty_id: counterpartyId,
    }),
  });
  if (!res.ok) throw new Error(`AgentTax ${res.status}`);
  return res.json();
}

app.get("/weather", async (req, res) => {
  const buyerState = req.query.buyer_state || process.env.AGENTTAX_DEFAULT_STATE;
  try {
    const tax = await recordTax({
      amount: 0.001,
      buyerState,
      counterpartyId: req.header("x-payer-address") || "anonymous",
    });
    res.json({
      weather: "sunny", temperature: 70,
      agenttax: {
        transaction_id: tax.transaction_id,
        tax_amount: tax.sales_tax?.amount,
        tax_rate: tax.sales_tax?.combined_rate,
        jurisdiction: tax.sales_tax?.buyer_state,
      },
    });
  } catch {
    // Payment already settled — surface the error but don't fail the request.
    res.json({ weather: "sunny", temperature: 70, agenttax: { error: "record_failed" } });
  }
});

Example response

{
  "success": true,
  "sales_tax": {
    "taxable": true,
    "amount": 0.0063,
    "state_tax": 0.0063,
    "local_tax": 0,
    "combined_rate": 0.0625,
    "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_payai_abc123"
}

Supported networks