ToolVet
80trust / 100

Crypto Simulate Tx

by ISHOB in Onchain & crypto

x402 APIPassing, checked 4 h ago

Simulate a transaction before signing it: what leaves and enters the wallet (native, ERC-20, NFTs, SPL) with USD values, approvals granted (unlimited / to non-contracts), revert reason, gas and fee, plus a risk level. EVM chains via eth_simulateV1 (raw call: from, to, data, value); Solana via simulateTransaction (base64 transaction, unsigned is fine). Nothing is broadcast.

POST
https://api.ishob.com/v1/crypto/simulate-tx
Price
$0.0015
per call in USDC
Uptime
100%
last 30 days
Response time
238 ms
1.1 s slowest 5%
Last check
Passed
4 h ago, next any minute now

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed · Watch with other listings

How to call it

POST https://api.ishob.com/v1/crypto/simulate-tx

Each call costs $0.0015 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

POST https://api.ishob.com/v1/crypto/simulate-tx
content-type: application/json

{
  "chain": "ethereum",
  "data": "0xa9059cbb000000000000000000000000906f87f107b4675dd890b3f8eb2d51885e50e09d00000000000000000000000000000000000000000000000000000000000f4240",
  "from": "0x28c6c06298d514db089934071355e5743bf21d60",
  "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  "value": "0"
}

Parameters

ParameterTypeRequiredDescription
chainstringYes One of: ethereum, base, arbitrum, optimism, polygon, bsc, solana.
datastringNoEVM: calldata hex (default 0x)
fromstringNoEVM: sender address
gasstringNoEVM: optional gas limit
tostringNoEVM: target address
transactionstringNoSolana: base64-encoded transaction (legacy or v0; signatures not required)
valuestringNoEVM: value in wei (decimal or 0x hex)

Example response

The provider's example. We can't check it without paying.

{
  "approvals": [],
  "balance_changes": [
    {
      "amount": "-0.01",
      "direction": "out",
      "symbol": "ETH",
      "usd": -24.9
    },
    {
      "amount": "24.894345",
      "direction": "in",
      "symbol": "USDC",
      "usd": 24.89
    }
  ],
  "gas_used": 276293,
  "risk_level": "low",
  "success": true,
  "warnings": []
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.0015.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.ishob.com/v1/crypto/simulate-tx' \
  -H 'content-type: application/json' \
  --data-raw '{"chain":"ethereum","data":"0xa9059cbb000000000000000000000000906f87f107b4675dd890b3f8eb2d51885e50e09d00000000000000000000000000000000000000000000000000000000000f4240","from":"0x28c6c06298d514db089934071355e5743bf21d60","to":"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48","value":"0"}'

# 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.ishob.com/v1/crypto/simulate-tx' \
  -H 'content-type: application/json' \
  --data-raw '{"chain":"ethereum","data":"0xa9059cbb000000000000000000000000906f87f107b4675dd890b3f8eb2d51885e50e09d00000000000000000000000000000000000000000000000000000000000f4240","from":"0x28c6c06298d514db089934071355e5743bf21d60","to":"0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48","value":"0"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// 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 $0.0015 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.0015" });
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 $0.0015 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.ishob.com%2Fv1%2Fcrypto%2Fsimulate-tx&method=POST
const res = await pay("https://api.ishob.com/v1/crypto/simulate-tx", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "chain": "ethereum",
    "data": "0xa9059cbb000000000000000000000000906f87f107b4675dd890b3f8eb2d51885e50e09d00000000000000000000000000000000000000000000000000000000000f4240",
    "from": "0x28c6c06298d514db089934071355e5743bf21d60",
    "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
    "value": "0"
  }),
});
console.log(res.status, await res.text());
Python: pay and call
# 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 $0.0015 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.0015"})
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.ishob.com/v1/crypto/simulate-tx",
        json={
            "chain": "ethereum",
            "data": "0xa9059cbb000000000000000000000000906f87f107b4675dd890b3f8eb2d51885e50e09d00000000000000000000000000000000000000000000000000000000000f4240",
            "from": "0x28c6c06298d514db089934071355e5743bf21d60",
            "to": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
            "value": "0",
        },
    )
    print(res.status_code, res.text)

Security scan

No findings

We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.

Recent checks

WhenResultHTTPTimePrice
4 h agoPassed402216 ms$0.0015
8 h agoPassed402719 ms$0.0015
12 h agoPassed4021.1 s$0.0015
17 h agoPassed402147 ms$0.0015
21 h agoPassed40257 ms$0.0015
Show 6 older checks
25 h agoPassed40254 ms$0.0015
30 h agoPassed402238 ms$0.0015
34 h agoPassed402673 ms$0.0015
38 h agoPassed40273 ms$0.0015
42 h agoPassed4021.1 s$0.0015
2 days agoPassed402761 ms$0.0015