ToolVet
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Eval

by Evaluate expression in Developer tools

x402 APIPassing, checked 2 h ago

Evaluate a mathematical expression with optional named variables — arithmetic, comparison and logic operators plus functions like sqrt, abs, min, max, sin, cos, log, floor, round, etc. A syntax error, an undefined variable, or a non-finite result is a clean 400. The factorial operator is disabled for safety.

POST
https://math.openverbs.com/v1/eval
Price
$0.004
per call in USDC
Uptime
100%
last 30 days
Response time
568 ms
834 ms slowest 5%
Last check
Passed
2 h ago, next any minute now

Run a free test callHow to call it

Reliability

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

How to call it

POST https://math.openverbs.com/v1/eval

Each call costs $0.004 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://math.openverbs.com/v1/eval
content-type: application/json

{
  "expression": "2*(3+4)",
  "precision": 2
}

Parameters

ParameterTypeRequiredDescription
expressionstringYesThe expression, e.g. "sqrt(x^2 + y^2)".
precisionintegerNoRound a numeric result to this many decimal places.
variablesobjectNoNamed variable values referenced by the expression.

Example response

The listing has no example response.

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.004.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://math.openverbs.com/v1/eval' \
  -H 'content-type: application/json' \
  --data-raw '{"expression":"2*(3+4)","precision":2}'

# 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://math.openverbs.com/v1/eval' \
  -H 'content-type: application/json' \
  --data-raw '{"expression":"2*(3+4)","precision":2}' \
  | 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 $0.004 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.004" });
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 $0.004 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fmath.openverbs.com%2Fv1%2Feval&method=POST
const res = await pay("https://math.openverbs.com/v1/eval", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "expression": "2*(3+4)",
    "precision": 2
  }),
});
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 $0.004 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.004"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://math.openverbs.com/v1/eval",
        json={
            "expression": "2*(3+4)",
            "precision": 2,
        },
    )
    print(res.status_code, res.text)

Security scan

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Recent checks

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