Contract Events

{
  "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "event": "Transfer(address,address,uint256)",
  "events": [
    {
      "block": 52083754,
      "hash": "0x359530c6c0662f964433082b08488f565b893a9c54083a6edb12b3e04a8333d5",
      "values": {
        "from": "0x61040E143A77F165Ba44543AF4A079F2C809D14b",
        "to": "0x41D4934322f2bd6fE1dbe4124070FE61651A2067",
        "value": "83126144588"
      }
    },
    {
      "block": 52083754,
      "hash": "0x48d57ad6140d5c2a949f7ce0dcdfff54cc13f75010a762428c9080f0ac26e5fe",
      "values": {
        "from": "0x787fD1dc3b533171781e4Ae1A563c1AC7b4435E4",
        "to": "0xb2cc224c1c9feE385f8ad6a55b4d94E92359DC59",
        "value": "149022949510"
      }
    }
  ],
  "found": 1957,
  "network": "base",
  "note": "Dynamic values (non-indexed string/bytes) are returned as a raw word.",
  "reviewed_blocks": 20,
  "topic0": "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.vextorium.com/v1/contract-events' \
  -H 'content-type: application/json' \
  --data-raw '{"blocks":20,"contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","event":"Transfer(address indexed from,address indexed to,uint256 value)","limit":3,"network":"base"}'

# 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://api.vextorium.com/v1/contract-events' \
  -H 'content-type: application/json' \
  --data-raw '{"blocks":20,"contract":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","event":"Transfer(address indexed from,address indexed to,uint256 value)","limit":3,"network":"base"}' \
  | 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%2Fapi.vextorium.com%2Fv1%2Fcontract-events&method=POST
const res = await pay("https://api.vextorium.com/v1/contract-events", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "blocks": 20,
    "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "event": "Transfer(address indexed from,address indexed to,uint256 value)",
    "limit": 3,
    "network": "base"
  }),
});
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://api.vextorium.com/v1/contract-events",
        json={
            "blocks": 20,
            "contract": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "event": "Transfer(address indexed from,address indexed to,uint256 value)",
            "limit": 3,
            "network": "base",
        },
    )
    print(res.status_code, res.text)