License Expression Check

{
  "asOf": "2026-10-11T14:39:35.213Z",
  "attribution": "License list: SPDX (CC0-1.0). Summaries: Choose a License (choosealicense.com, CC BY 3.0).",
  "degraded": false,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "exceptions": [
    {
      "canonicalId": "Classpath-exception-2.0",
      "id": "Classpath-exception-2.0",
      "name": "Classpath exception 2.0",
      "status": "valid"
    }
  ],
  "expression": "GPL-2.0-or-later WITH Classpath-exception-2.0 OR MIT",
  "licenses": [
    {
      "canonicalId": "GPL-2.0-or-later",
      "id": "GPL-2.0-or-later",
      "name": "GNU General Public License v2.0 or later",
      "osiApproved": true,
      "plusOnDeprecated": false,
      "status": "valid"
    },
    {
      "canonicalId": "MIT",
      "id": "MIT",
      "name": "MIT License",
      "osiApproved": true,
      "plusOnDeprecated": false,
      "status": "valid"
    }
  ],
  "listVersion": "3.29.0",
  "notChecked": [
    "what the expression means legally: AND/OR do not tell you which terms you may choose",
    "LicenseRef-* and DocumentRef-* custom identifiers (accepted by form, not resolved)",
    "…1 more"
  ],
  "operators": [
    "WITH",
    "OR"
  ],
  "reasons": [
    "License list: SPDX (CC0-1.0). Summaries: Choose a License (choosealicense.com, CC BY 3.0).",
    "OR means the recipient may choose; AND means all apply; WITH adds an exception to one license."
  ],
  "source": "SPDX License List + Choose a License",
  "sourceUrl": "https://spdx.org/licenses/",
  "summary": "Valid SPDX expression; 2 licenses, operators: WITH, OR.",
  "verdict": "VALID",
  "warnings": []
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://license-intel.x402tookit.com/license-expression-check?expression=GPL-2.0-or-later+WITH+Classpath-exception-2.0+OR+MIT'

# 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 - 'https://license-intel.x402tookit.com/license-expression-check?expression=GPL-2.0-or-later+WITH+Classpath-exception-2.0+OR+MIT' \
  | 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 $0.03 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.03" });
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 $0.03 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Flicense-intel.x402tookit.com%2Flicense-expression-check
const res = await pay("https://license-intel.x402tookit.com/license-expression-check?expression=GPL-2.0-or-later+WITH+Classpath-exception-2.0+OR+MIT");
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 $0.03 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.03"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://license-intel.x402tookit.com/license-expression-check?expression=GPL-2.0-or-later+WITH+Classpath-exception-2.0+OR+MIT")
    print(res.status_code, res.text)