Color Blind Sim

{
  "asOf": "2026-10-11T04:02:40.219Z",
  "background": "#2ecc71",
  "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.",
  "normalContrast": 1.82,
  "notChecked": [
    "partial (anomalous) color vision, which is more common than full dichromacy",
    "monochromacy",
    "…1 more"
  ],
  "original": "#e74c3c",
  "reasons": [
    "Machado, Oliveira and Fernandes (2009) matrices at full severity, applied in linear RGB.",
    "Red-green pairs that differ only in hue are the usual failure: add a lightness difference."
  ],
  "simulations": {
    "deuteranopia": {
      "background": "#baae77",
      "color": "#9f8f36",
      "contrast": 1.46
    },
    "protanopia": {
      "background": "#ccbb6a",
      "color": "#786d39",
      "contrast": 2.68
    },
    "tritanopia": {
      "background": "#00c9b6",
      "color": "#fe1b49",
      "contrast": 1.84
    }
  },
  "source": "computed locally",
  "summary": "#e74c3c on #2ecc71: 1.82:1 normally; protanopia 2.68:1, deuteranopia 1.46:1, tritanopia 1.84:1.",
  "verdict": "PAIR_HOLDS_UP"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://color-design.x402tookit.com/color-blind-sim?background=2ecc71&color=e74c3c'

# 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://color-design.x402tookit.com/color-blind-sim?background=2ecc71&color=e74c3c' \
  | 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 $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
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 $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fcolor-design.x402tookit.com%2Fcolor-blind-sim
const res = await pay("https://color-design.x402tookit.com/color-blind-sim?background=2ecc71&color=e74c3c");
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 $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://color-design.x402tookit.com/color-blind-sim?background=2ecc71&color=e74c3c")
    print(res.status_code, res.text)