Preflight

{
  "facts": {
    "bazaar": {
      "available": true,
      "host_listing_count": 3,
      "last_called_at": "2026-10-14T12:00:00Z",
      "listed": true,
      "listed_payTo": [
        "0x742d35cc6634c0532925a3b844bc454e4438f44e"
      ],
      "payer_trend": [
        {
          "calls30d": 17,
          "payers30d": 4,
          "snapshot": "2026-10-15"
        }
      ],
      "payout_wallet_reuse": {},
      "snapshot_date": "2026-10-15"
    },
    "challenge": {
      "accepts": [],
      "problems": [],
      "valid": true
    },
    "checked_at": "2026-10-15T00:00:00Z",
    "disclaimer": "Deterministic observations only. Not advice to pay, buy or sell.",
    "reachability": {
      "http_status": 402,
      "latency_ms": 180,
      "reachable": true
    },
    "schema": "prepay-check/v1",
    "target": "https://x402.org/protected"
  },
  "signature": {
    "alg": "Ed25519",
    "key_id": "72cb9da845cc948f",
    "public_key_b64": "C3wmUnTtL12LUfkfDCR0bIeUXjbfq+hde5OeQC+dUy0=",
    "signed_over": "canonical JSON of facts (sorted keys, no whitespace)",
    "value_b64": "base64 Ed25519 signature over the canonical facts"
  }
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://base-reads-api.rafliyaputra.deno.net/x402/preflight?url=https%3A%2F%2Fx402.org%2Fprotected'

# 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 - 'https://base-reads-api.rafliyaputra.deno.net/x402/preflight?url=https%3A%2F%2Fx402.org%2Fprotected' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// 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 $0.001 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.001" });
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 $0.001 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fbase-reads-api.rafliyaputra.deno.net%2Fx402%2Fpreflight
const res = await pay("https://base-reads-api.rafliyaputra.deno.net/x402/preflight?url=https%3A%2F%2Fx402.org%2Fprotected");
console.log(res.status, await res.text());

# 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 $0.001 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.001"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://base-reads-api.rafliyaputra.deno.net/x402/preflight?url=https%3A%2F%2Fx402.org%2Fprotected")
    print(res.status_code, res.text)