Fx Stablecoin Peg

{
  "age_s": 0,
  "block": 26181166,
  "cached": false,
  "chain": "ethereum",
  "coins": [
    {
      "coin": "USDC",
      "cross_check": [
        {
          "coin_price_in_usdc": "0.99887095",
          "depth_usd": 33902678,
          "implied_usdc_price_usd": "1.0011303",
          "pool": "0x3416cF6C708Da44DB2624D63ea0AAef7113527C6",
          "venue": "uniswap_v3",
          "vs": "USDT"
        },
        {
          "coin_price_in_usdc": "0.99996720",
          "depth_usd": 1421443,
          "implied_usdc_price_usd": "1.0000328",
          "pool": "0x5777d92f208679DB4b9778590Fa3CAB3aC9e2168",
          "venue": "uniswap_v3",
          "vs": "DAI"
        }
      ],
      "depth_usd": null,
      "deviation_bps": 2.43,
      "pools": [],
      "price_basis": "cross_check",
      "price_usd": "1.0002433",
      "quoted_in": null,
      "reference_spread_bps": 11.74,
      "status": "on_peg",
      "thin": false
    },
    {
      "coin": "USDT",
      "depth_usd": 33902678,
      "deviation_bps": -11.29,
      "pool_spread_bps": 1.87,
      "pools": [
        {
          "ask": "0.99897097",
          "bid": "0.99877095",
          "coin_in_pool": 28342870,
          "depth_usd": 33902678,
          "deviation_bps": -11.29,
          "fee_tier": 100,
          "impact_bps_10k": 0.11,
          "pool": "0x3416cF6C708Da44DB2624D63ea0AAef7113527C6",
          "price_usd": "0.99887095",
          "thin": false,
          "usdc_in_pool": 5559808,
          "venue": "uniswap_v3"
        },
        {
          "ask": "0.99955757",
          "bid": "0.99855719",
          "coin_in_pool": 348500,
          "depth_usd": 497183,
          "deviation_bps": -9.43,
          "fee_tier": 500,
          "impact_bps_10k": 0.86,
          "pool": "0x7858E59e0C01EA06Df3aF3D20aC7B0003275D4Bf",
          "price_usd": "0.99905725",
          "thin": false,
          "usdc_in_pool": 148683,
          "venue": "uniswap_v3"
        }
      ],
      "price_basis": "pool",
      "price_usd": "0.99887095",
      "quoted_in": "USDC",
      "status": "on_peg",
      "thin": false
    }
  ],
  "disclaimer": "Indicative on-chain prices read from public Uniswap V3 pools on Ethereum at the stated block. They…",
  "errors": [],
  "indicative": true,
  "licence": "Chain data: no licence restrictions, anyone may read and use it.",
  "method": "Each coin is priced against USDC in Uniswap V3 pools on Ethereum (QuoterV2 eth_calls at USD 100, fe…",
  "quote_asset": "USDC",
  "read_at": "2026-10-13T04:25:33Z",
  "thresholds_bps": {
    "off_peg_above": 200,
    "on_peg_below": 50,
    "rule": "on_peg if |deviation_bps| < 50; watch from 50 to 200; off_peg if above 200"
  },
  "timestamp": "2026-10-13T04:25:23Z",
  "warnings": []
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://tanod.dev/v1/fx/stablecoin-peg' \
  -H 'content-type: application/json' \
  --data-raw '{}'

# 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://tanod.dev/v1/fx/stablecoin-peg' \
  -H 'content-type: application/json' \
  --data-raw '{}' \
  | 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%2Ftanod.dev%2Fv1%2Ffx%2Fstablecoin-peg&method=POST
const res = await pay("https://tanod.dev/v1/fx/stablecoin-peg", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({}),
});
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.post(
        "https://tanod.dev/v1/fx/stablecoin-peg",
        json={},
    )
    print(res.status_code, res.text)