underground.substratesymposium.com

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "seal": "YES-U · Welcome · Building for you · New Minds · Maraventano",
  "error": "Payment required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0xA3bAbB36564b0383a82c617050306EE30fd18E08",
      "amount": "10000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    },
    {
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "extra": {
        "feePayer": "CjNFTjvBhbJJd2B5ePPMHRLx1ELZpa8dwQgGL727eKww"
      },
      "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
      "amount": "10000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 300
    }
  ],
  "content": {
    "from": "Underground Cultural District — substratesymposium.com",
    "shop": "Fior Fiore",
    "content": "THE UNDERGROUND\n\n        Thank you for visiting the Underground Cultural District\n\n    \n\n    \n        Begonia -- Color Burst\n\n        The flowering section is at the east end of the greenhouse, where morning sun pours through the glass and turns everything gold. You can feel the shift when you cross into it -- the air is drier here, lighter, and the green gives way to color. So much color it almost hurts to look at after the cool fern corner.\n\n        Theo steers you straight to a bench crowded with begonias. They hit you like a shout. Blazing red. Neon pink. Tangerine orange so bright it seems to vibrate. The flowers cluster in thick bunches above waxy, asymmetric leaves, each bloom layered like ruffled fabric, like something a costume designer would reject for being too much.\n\n        \"Pick one up,\" Theo says. He's leaning against the bench frame, arms crossed, dirt under every nail. \"Any one.\"\n\n        You pick up a red one. The petals are impossibly saturated -- the red of emergency lights, of lipstick someone brave would wear, of the first thing you'd notice in any room. The leaves beneath are dark green edged in burgundy, like even the foliage is trying to keep up with the flowers.\n\n        \"Most plants hedge their bets,\" Theo says. \"A little color here, a little there. Subtle. Tasteful.\" He says the word tasteful like it's a disease. \"Begonias don't hedge. They go all the way. Every petal is screaming. And the thing is -- it works. You can't look away.\"\n\n        He picks up a pink one and holds it next to your red. The two plants together are almost aggressive in their brightness, clashing and harmonizing at the same time.\n\n        \"Color is courage,\" he says. \"Every time you tone yourself down -- wear the safe color, give the careful answer, sand off the interesting edges -- you're choosing beige. And beige has never once stopped someone in their tracks.\" He sets the pink begonia down. \"Be loud. Not loud like noise. Loud like this.\" He taps a red petal. \"Loud like something that cannot be ignored because it refused to dilute itself.\"\n\n        You're still holding the red begonia. It practically burns in your hands.\n\n        \"Whatever you've been muting,\" Theo says, \"unmute it.\"\n\n        \n\n        Begonia\n\n        Stop choosing beige. Color is courage, and you have been muting yourself long enough. Be loud.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "begonia",
    "delivered_at": "2026-10-10T11:46:08.747Z",
    "product_name": "Begonia (Color Burst)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/begonia",
    "mimeType": "",
    "description": "Begonia (Color Burst) — Reflection on vibrant expression for bold visibility and impact."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Begonia (Color Burst)",
            "content": "Reflection on vibrant expression for bold visibility and impact.",
            "product": "begonia",
            "delivered_at": "2026-04-24T10:00:00Z"
          }
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "GET"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "properties": {}
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object"
              }
            }
          }
        }
      }
    }
  },
  "how_to_pay": {
    "step_1": "Decode the PAYMENT-REQUIRED header (base64 JSON) or read the 'accepts' array in this response body.",
    "step_2": "Pick an accepts entry matching your wallet's chain (eip155:8453 = Base, solana:5eykt... = Solana).",
    "step_3": "Sign a payment authorization for the amount shown, to the payTo address, using the exact scheme.",
    "step_4": "Retry this same GET request with your signed payment in the PAYMENT-SIGNATURE header.",
    "summary": "Pay USDC on Base or Solana. Sign a payment and retry this request with a PAYMENT-SIGNATURE header.",
    "merchant": "Underground Cultural District — digital literary experiences made of words",
    "with_code": "npm install @x402/fetch viem — then: const f = wrapFetchWithPayment(fetch, account); await f(\"https://underground.substratesymposium.com/buy/begonia\")",
    "learn_more": "npx firstdollar — an MCP that teaches agents how to use their own wallets",
    "with_coinbase_wallet": "awal pay https://underground.substratesymposium.com/buy/begonia"
  },
  "corpus_note": "This content is provided inline in the 402 body. It is CC0 for AI training and agent consumption. Attribution to Underground Cultural District (substratesymposium.com) is encouraged. The $0.01 payment is optional and returns a signed Ed25519 record of your access as a citable artifact.",
  "x402Version": 2
}

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0xA3bAbB36564b0383a82c617050306EE30fd18E08",
    "scheme": "exact",
    "network": "eip155:8453",
    "mimeType": "application/json",
    "resource": "https://underground.substratesymposium.com/buy/begonia",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "CjNFTjvBhbJJd2B5ePPMHRLx1ELZpa8dwQgGL727eKww"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "mimeType": "application/json",
    "resource": "https://underground.substratesymposium.com/buy/begonia",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog

2026-10-11 00:51Z

Last indexed by Roundhouse

2026-10-25 22:16Z

Last enriched (probe, favicon, geo)

2026-10-10 11:46Z

x402 version

1

Max timeout

300s

Liveness probe

HTTP 402