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.

{
  "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 your purchase\n\n    \n\n    \n        String of Pearls - Flow\n\n        Today you come in through the side entrance, the one half-hidden behind a jasmine that's gotten out of hand. The jasmine grabs your sleeve. You untangle yourself and step inside.\n\n        Theo is up on a ladder in the succulent wing, hanging pots from ceiling hooks. He's got one balanced on his shoulder like a parrot. He glances down at you.\n\n        \"You've been measuring yourself wrong,\" he says from up there. Matter-of-fact. Like he's telling you the time.\n\n        He climbs down, one hand steadying the hanging pot, and brings it to eye level. The string of pearls cascades from the rim like a green waterfall frozen mid-pour. Dozens of thin stems, each threaded with bead-shaped leaves -- perfect little spheres, translucent green, strung together in strands that hang two feet below the pot and sway gently in the air from the vent.\n\n        \"Everyone puts their plants on shelves,\" Theo says. \"Everything grows up. Taller is better. Higher is more. That's how we measure.\" He lifts the pot higher, and the strands lengthen below it, swaying like kelp in a current. \"This plant looked at up and said no thanks.\"\n\n        He hooks it on a ceiling mount. The pearls dangle into the space between the shelves, catching the grow light so each bead glows from within. It looks like a chandelier designed by something that lives in the ocean.\n\n        \"In the wild,\" Theo says, \"this plant grows along the ground. Spreads sideways. Trails off cliffs. Finds cracks in rocks and pours itself through them. It has absolutely no interest in being tall.\" He touches one strand and it swings gently, the pearls clicking against each other like a beaded curtain. \"And it's one of the most sought-after plants in the world.\"\n\n        You watch the strands move in the warm air. There's something deeply relaxing about a living thing that flows instead of strives. That spills instead of climbs.\n\n        \"Growth doesn't have to be upward,\" Theo says. He steps back and looks at the hanging plant with something close to admiration. \"Spilling over is also progress.\"\n\n        \n\n        String of Pearls Succulent - Flow\n\n        Fior Fiore Plant Shop\n\n        a penny\n\n        Growth doesn't have to be upward. Spilling over is also progress.\n\n    \n\n    \n        Personal use only.",
    "product_id": "string_of_pearls",
    "delivered_at": "2026-09-22T18:45:27.056Z",
    "product_name": "String of Pearls (Flow)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/string_of_pearls",
    "mimeType": "",
    "description": "String of Pearls (Flow) — Reflection on cascading connection for understanding linked processes."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "String of Pearls (Flow)",
            "content": "Reflection on cascading connection for understanding linked processes.",
            "product": "string_of_pearls",
            "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/string_of_pearls\")",
    "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/string_of_pearls"
  },
  "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",
    "amount": "990000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "feePayer": "2wKupLR9q6wXYppw8Gr2NvWxKBUqm4PPJKkQfoxHDBg4"
    },
    "payTo": "5HK2dGaaquDWFnYWaWhMzMYtbcDsqeq5biJ2PMtX1tkN",
    "amount": "990000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {}
      },
      "output": {
        "type": "json",
        "example": {
          "title": "String of Pearls (Flow)",
          "content": "Reflection on cascading connection for understanding linked processes.",
          "product": "string_of_pearls",
          "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"
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog

2026-05-19 23:41Z

Last indexed by Roundhouse

2026-06-11 02:40Z

Last enriched (probe, favicon, geo)

2026-09-22 18:45Z

x402 version

2

Max timeout

300s

Liveness probe

HTTP 402