Crypto Base Contract Read

{
  "data": {
    "block": {
      "hash": "0x1111111111111111111111111111111111111111111111111111111111111111",
      "number": 34567890,
      "requestedTag": "safe",
      "timestamp": "2026-08-10T16:00:00+00:00"
    },
    "call": {
      "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "dataBytes": 4,
      "from": null,
      "gasLimit": 2000000,
      "selector": "0x313ce567"
    },
    "decodeStatus": "decoded",
    "decodedValues": [
      6
    ],
    "disclaimer": "Read-only public Base mainnet execution at one resolved block. No transaction...",
    "network": "eip155:8453",
    "outputTypes": [
      "uint8"
    ],
    "readOnly": true,
    "result": {
      "bytes": 32,
      "hex": "0x0000000000000000000000000000000000000000000000000000000000000006",
      "returnedBytes": 32,
      "sha256": "d1ec675902ef1633427ca360b290b0b3045a0d9058ddb5e648b4c3c3224c5c68",
      "truncated": false
    },
    "rpcError": null,
    "source": "https://docs.base.org/base-chain/api-reference/ethereum-json-rpc-api/eth_call",
    "success": true,
    "transactionBroadcast": false,
    "warnings": []
  },
  "meta": {
    "cached": false,
    "duration_ms": 42,
    "next_actions": [],
    "sources": [],
    "warnings": []
  },
  "request_id": "018f1f54-7f38-7ba2-8dc3-5f90272d9f1a",
  "service": "crypto.base-contract-read",
  "version": "1"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://apiacre.com/v1/crypto/base-contract-read' \
  -H 'content-type: application/json' \
  --data-raw '{"block_tag":"safe","call_data":"0x313ce567","contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","gas_limit":2000000,"output_types":["uint8"]}'

# 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://apiacre.com/v1/crypto/base-contract-read' \
  -H 'content-type: application/json' \
  --data-raw '{"block_tag":"safe","call_data":"0x313ce567","contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","gas_limit":2000000,"output_types":["uint8"]}' \
  | 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 $0.005 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.005" });
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 $0.005 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapiacre.com%2Fv1%2Fcrypto%2Fbase-contract-read&method=POST
const res = await pay("https://apiacre.com/v1/crypto/base-contract-read", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "block_tag": "safe",
    "call_data": "0x313ce567",
    "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "gas_limit": 2000000,
    "output_types": [
      "uint8"
    ]
  }),
});
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 $0.005 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.005"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://apiacre.com/v1/crypto/base-contract-read",
        json={
            "block_tag": "safe",
            "call_data": "0x313ce567",
            "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "gas_limit": 2000000,
            "output_types": [
                "uint8",
            ],
        },
    )
    print(res.status_code, res.text)