Chain Quote

{
  "amount_in": "1",
  "amount_in_raw": "1000000000000000000",
  "amount_out": "2581.028349",
  "amount_out_raw": "2581028349",
  "block": 52290474,
  "chain": "base",
  "dex": "uniswap_v3",
  "disclaimer": "On-chain spot quote from Uniswap V3 QuoterV2 at the latest block: one pool, exact input, no gas or other venues included. Not a firm price or an execution guarantee; it changes every block and can be manipulated, especially for illiquid pools. Do not use it as an oracle.",
  "failed_tiers": [],
  "fee_tier": 100,
  "gas_estimate": "75682",
  "price": "2581.028349",
  "quoter": "0x3d4e44Eb1374240CE5F1B871ab261CD16335B76a",
  "tiers": [
    {
      "amount_out_raw": "2581028349",
      "fee": 100,
      "gas_estimate": "75682",
      "initialized_ticks_crossed": 0
    },
    {
      "amount_out_raw": "2579463015",
      "fee": 500,
      "gas_estimate": "75740",
      "initialized_ticks_crossed": 1
    },
    {
      "amount_out_raw": "2574527842",
      "fee": 3000,
      "gas_estimate": "72853",
      "initialized_ticks_crossed": 1
    },
    {
      "amount_out_raw": "2566901997",
      "fee": 10000,
      "gas_estimate": "81545",
      "initialized_ticks_crossed": 1
    }
  ],
  "token_in": {
    "address": "0x4200000000000000000000000000000000000006",
    "decimals": 18,
    "symbol": "WETH"
  },
  "token_out": {
    "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "decimals": 6,
    "symbol": "USDC"
  }
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://tanod.dev/v1/chain/quote' \
  -H 'content-type: application/json' \
  --data-raw '{"amount_in":"1","chain":"base","token_in":"0x4200000000000000000000000000000000000006","token_out":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}'

# 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/chain/quote' \
  -H 'content-type: application/json' \
  --data-raw '{"amount_in":"1","chain":"base","token_in":"0x4200000000000000000000000000000000000006","token_out":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}' \
  | 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 $0.003 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.003" });
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 $0.003 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Ftanod.dev%2Fv1%2Fchain%2Fquote&method=POST
const res = await pay("https://tanod.dev/v1/chain/quote", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "amount_in": "1",
    "chain": "base",
    "token_in": "0x4200000000000000000000000000000000000006",
    "token_out": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
  }),
});
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 $0.003 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.003"})
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/chain/quote",
        json={
            "amount_in": "1",
            "chain": "base",
            "token_in": "0x4200000000000000000000000000000000000006",
            "token_out": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        },
    )
    print(res.status_code, res.text)