underground.substratesymposium.com · catalog

Underground Cultural District — catalog of 228 themed digital products (poetry, philosophy, fiction, reflection, plant meditations). One settle returns the full menu with every product's slug, description, price, and x402 endpoint. Each individual product is its own indexable x402 route. The catalog is the doorway.

Call it in 30 seconds

// npm i x402-fetch viem
import { wrapFetchWithPayment } from "x402-fetch";
import { createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { base } from "viem/chains";

const account = privateKeyToAccount(process.env.PRIVATE_KEY); // funds USDC on Base
const wallet = createWalletClient({ account, chain: base, transport: http() });
const fetchWithPay = wrapFetchWithPayment(fetch, wallet);

// Pays the $0.01 USDC automatically on the 402, then returns the real response:
const res = await fetchWithPay("https://underground.substratesymposium.com/buy/catalog", { method: "GET" });
console.log(await res.json());

# pip install x402 eth-account httpx
import os, asyncio
from eth_account import Account
from x402.clients.httpx import x402HttpxClient

account = Account.from_key(os.environ["PRIVATE_KEY"])  # funds USDC on Base

async def main():
    async with x402HttpxClient(account=account) as client:
        # x402 handles the 402 -> pay ($0.01 USDC) -> retry automatically
        r = await client.get("https://underground.substratesymposium.com/buy/catalog")
        print((await r.aread()).decode())

asyncio.run(main())

# 1) An unpaid request returns HTTP 402 with the exact payment terms:
curl -i "https://underground.substratesymposium.com/buy/catalog"

# 2) Paying + retrying requires an x402 client that can sign the USDC
#    authorization (curl alone cannot). See the JS / Python tabs below.

New to x402? Read the 5-minute quickstart →