ToolVet
77trust / 100

Read Contract

by chain.openverbs.com in Onchain & crypto

x402 APIPassing, checked 3 h ago

Call a read-only (view/pure) function on any deployed contract via eth_call and get the decoded result. Give the contract address and a human-readable signature (e.g. 'balanceOf(address) view returns (uint256)') plus args; include return types to decode outputs, else raw hex is returned. Reads allowances, oracle prices and vault/DAO state. Read-only, no signing. Ethereum, Base, Arbitrum, Optimism, Polygon.

POST
https://chain.openverbs.com/v1/read-contract
Price
$0.006
per call in USDC
Uptime
100%
last 30 days
Response time
533 ms
606 ms slowest 5%
Last check
Passed
3 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://chain.openverbs.com/v1/read-contract

Each call costs $0.006 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://chain.openverbs.com/v1/read-contract
content-type: application/json

{
  "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "chain": "base",
  "function": "decimals() view returns (uint8)"
}

Parameters

ParameterTypeRequiredDescription
addressstringYesDeployed contract address.
argsarrayNoFunction arguments in order (numbers may be passed as strings).
blockinteger or stringNoBlock number or tag (latest, earliest, pending, safe, finalized). Default latest.
chainstringNoEVM chain to query. One of: ethereum, base, arbitrum, optimism, polygon. Default "ethereum". One of: ethereum, base, arbitrum, optimism, polygon.
functionstringYesHuman-readable function signature, e.g. "balanceOf(address) view returns (uint256)". Include the return types to decode the result.

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 $0.006.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://chain.openverbs.com/v1/read-contract' \
  -H 'content-type: application/json' \
  --data-raw '{"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","chain":"base","function":"decimals() view returns (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://chain.openverbs.com/v1/read-contract' \
  -H 'content-type: application/json' \
  --data-raw '{"address":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","chain":"base","function":"decimals() view returns (uint8)"}' \
  | 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 $0.006 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.006" });
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 $0.006 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fchain.openverbs.com%2Fv1%2Fread-contract&method=POST
const res = await pay("https://chain.openverbs.com/v1/read-contract", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "chain": "base",
    "function": "decimals() view returns (uint8)"
  }),
});
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 $0.006 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.006"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://chain.openverbs.com/v1/read-contract",
        json={
            "address": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
            "chain": "base",
            "function": "decimals() view returns (uint8)",
        },
    )
    print(res.status_code, res.text)

Security scan

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3 h agoPassed402564 ms$0.006
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3 days agoPassed402552 ms$0.006