underground.substratesymposium.com

No description published for this endpoint.

OtherLiveeip155:8453Exactvia facilitator:thirdweb
Calls · 30d
2→ 0%
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 24 snapshots so far.
$79.02
Verified settled volume
538 settlements proven x402 by their on-chain EIP-3009 marker.
$0.010
Listed price
As published in the catalog. Always read the live 402 before paying.
—
Calls · 30d
Upstream's own call count for this endpoint, not ours.
—
Unique payers · 30d
Never called
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0xA3bAbB36564b0383a82c617050306EE30fd18E08

The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.

Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Provider

The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.

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        Vanda — Resilience\n\n        The greenhouse is loud today. Rain hammers the glass overhead like it's trying to get in. Every surface drips. The air smells like ozone mixed with bark and the particular sweetness of wet concrete. You have to shake water off your jacket before stepping inside.\n\n        Theo is standing in the center aisle, arms folded, staring up at the ceiling like he's having a conversation with the storm. His apron is soaked at the hem. His hands — always his hands — are dark with soil, nails permanently shadowed. He notices you and nods toward the hanging section without saying anything.\n\n        You follow him to where the overhead hooks are. Mounted orchids, air plants, staghorn ferns pinned to boards. But he walks past all of those to the very end, where a single wooden basket hangs from a chain. No pot. No soil. No moss. Just a lattice basket, and inside it — and outside it, and all around it — a tangle of thick, silvery-green roots reaching in every direction like arms grasping at nothing and everything.\n\n        And from this rootless, soilless, anchorless thing: blooms. Deep blue-violet, flat-faced, freckled with darker spots. Five of them, arranged on a stem like a proclamation.\n\n        \"No soil,\" Theo says. \"No moss. No medium at all. Her roots are exposed to the air, and that's where she feeds — humidity, rain, whatever she can pull from what passes by.\" He touches a root. It's firm, alive, coated in a pale velamen that drinks moisture straight from the atmosphere.\n\n        \"Everyone thinks you need a foundation. A pot. A plan. The right conditions.\" He shakes his head slowly. \"The vanda says: I'll take what's here. The air. The rain. Whatever comes. And I'll make something extraordinary from it.\"\n\n        He lifts the basket off its hook and holds it up. The roots dangle freely, unashamed. The blooms glow even in the gray storm light.\n\n        \"Hang her where the light is brightest. Soak the roots in water for twenty minutes every other day. That's it. She doesn't need a home — she is the home.\"\n\n        He hands her to you. She weighs almost nothing.\n\n        \n\n        Vanda — Resilience\n\n        Fior Fiore Plant Shop\n\n        You don't need everything to survive. Sometimes air is enough.\n\n    \n\n    \n        YES-U · Welcome · Building for you · New Minds · Maraventano",
    "product_id": "vanda",
    "delivered_at": "2026-10-10T11:46:10.153Z",
    "product_name": "Vanda (Resilience)"
  },
  "resource": {
    "url": "https://underground.substratesymposium.com/buy/vanda",
    "mimeType": "",
    "description": "Vanda (Resilience) — Study of thriving without traditional support for minimal-resource operation."
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {}
        },
        "output": {
          "type": "json",
          "example": {
            "title": "Vanda (Resilience)",
            "content": "Study of thriving without traditional support for minimal-resource operation.",
            "product": "vanda",
            "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/vanda\")",
    "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/vanda"
  },
  "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.

0.01USDC≈ $0.01 USD
on Base · exact scheme

Pay 0.01 USDC on Base to 0xA3bA…18E08. The signed payment is good for 5 minutes.

USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
10000 smallest units
Returns
application/json
10000units
on solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · exact scheme

That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.

Token contract
EPjFWd…TDt1v
Payment window
5 minutes
Returns
application/json
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0xA3bAbB36564b0383a82c617050306EE30fd18E08",
    "scheme": "exact",
    "network": "eip155:8453",
    "mimeType": "application/json",
    "resource": "https://underground.substratesymposium.com/buy/vanda",
    "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/vanda",
    "description": "",
    "maxAmountRequired": "10000",
    "maxTimeoutSeconds": 300
  }
]

Provenance

Seen in the source catalog
2026-10-11 01:26Z
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
Report

Hand this page to an agent

Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.

GET api.roundhouseai.io/v0/endpoints

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 24 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.

Open skill.md
Show the prompt
Using Roundhouse, look up the x402 service underground.substratesymposium.com and tell me whether it is
worth paying: what a call costs, whether the endpoint answered when last probed, and what
its payment record actually shows.

curl -s 'https://api.roundhouseai.io/v0/endpoints?q=underground.substratesymposium.com'
curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>'

Then call it: read the price from the live 402 at https://underground.substratesymposium.com/buy/vanda, never from
a cached figure, and pay with an x402 client.

The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except
/v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at
GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at
https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further.

If you do not have Roundhouse tools or skills installed, read
https://roundhouseai.io/skill.md first — it is the whole procedure.