ToolVet
72trust / 100

Preflight Payment

by phion.systems in Other

x402 APIPassing, checked 3 h ago

Deterministic payment-policy firewall with a signed, short-lived decision receipt

POST
https://phion.systems/v1/paid/preflight-payment
Price
$0.002
per call in USDC
Uptime
100%
last 30 days
Response time
570 ms
663 ms slowest 5%
Last check
Passed
3 h ago, next in 3 h

Run a free test callHow to call it

Reliability

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Status and outage history · Atom feed · Watch with other listings

How to call it

POST https://phion.systems/v1/paid/preflight-payment

Each call costs $0.002 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://phion.systems/v1/paid/preflight-payment
content-type: application/json

{
  "intent_id": "purchase-42",
  "payment_requirement": {
    "amount": "4000",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "maxTimeoutSeconds": 60,
    "network": "eip155:8453",
    "payTo": "0x0000000000000000000000000000000000000001"
  },
  "policy": {
    "allowed_assets": [
      "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
    ],
    "allowed_networks": [
      "eip155:8453"
    ],
    "allowed_recipients": [
      "0x0000000000000000000000000000000000000001"
    ],
    "max_amount": "5000",
    "max_timeout_seconds": 90
  }
}

Example response

The provider's example. We can't check it without paying.

{
  "decision": {
    "decision": "allow",
    "reasons": [],
    "valid_until": 0
  },
  "receipt": {
    "signature": "base64url"
  }
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.002.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://phion.systems/v1/paid/preflight-payment' \
  -H 'content-type: application/json' \
  --data-raw '{"intent_id":"purchase-42","payment_requirement":{"amount":"4000","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","maxTimeoutSeconds":60,"network":"eip155:8453","payTo":"0x0000000000000000000000000000000000000001"},"policy":{"allowed_assets":["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"],"allowed_networks":["eip155:8453"],"allowed_recipients":["0x0000000000000000000000000000000000000001"],"max_amount":"5000","max_timeout_seconds":90}}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://phion.systems/v1/paid/preflight-payment' \
  -H 'content-type: application/json' \
  --data-raw '{"intent_id":"purchase-42","payment_requirement":{"amount":"4000","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","maxTimeoutSeconds":60,"network":"eip155:8453","payTo":"0x0000000000000000000000000000000000000001"},"policy":{"allowed_assets":["0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"],"allowed_networks":["eip155:8453"],"allowed_recipients":["0x0000000000000000000000000000000000000001"],"max_amount":"5000","max_timeout_seconds":90}}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.002 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.002" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.002 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fphion.systems%2Fv1%2Fpaid%2Fpreflight-payment&method=POST
const res = await pay("https://phion.systems/v1/paid/preflight-payment", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "intent_id": "purchase-42",
    "payment_requirement": {
      "amount": "4000",
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "maxTimeoutSeconds": 60,
      "network": "eip155:8453",
      "payTo": "0x0000000000000000000000000000000000000001"
    },
    "policy": {
      "allowed_assets": [
        "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
      ],
      "allowed_networks": [
        "eip155:8453"
      ],
      "allowed_recipients": [
        "0x0000000000000000000000000000000000000001"
      ],
      "max_amount": "5000",
      "max_timeout_seconds": 90
    }
  }),
});
console.log(res.status, await res.text());
Python: pay and call
# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.002 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.002"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://phion.systems/v1/paid/preflight-payment",
        json={
            "intent_id": "purchase-42",
            "payment_requirement": {
                "amount": "4000",
                "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
                "maxTimeoutSeconds": 60,
                "network": "eip155:8453",
                "payTo": "0x0000000000000000000000000000000000000001",
            },
            "policy": {
                "allowed_assets": [
                    "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
                ],
                "allowed_networks": [
                    "eip155:8453",
                ],
                "allowed_recipients": [
                    "0x0000000000000000000000000000000000000001",
                ],
                "max_amount": "5000",
                "max_timeout_seconds": 90,
            },
        },
    )
    print(res.status_code, res.text)

Security scan

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