Roundhouse AI

saylorinnovations.com

Currency conversion (ECB reference rates, today or any date since 1999) — Real-world Data

DataLiveeip155:8453Exactvia cdp
https://saylorinnovations.com/api/util/fx
UtilityFx
Activity
—
Nothing indexed for this service or its provider yet. Not a claim that it is unused — only that we hold no record.
—
Verified settled volume
0 settlements proven x402 by their on-chain EIP-3009 marker.
$0.0010
Listed price
As published in the catalog. Always read the live 402 before paying.
3
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-09-24 21:17Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0xf8A376eBF123D7252cd7b66bcD77A727a4def22f

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.

{
  "error": "Payment required to access this resource.",
  "accepts": [
    {
      "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "extra": {
        "memo": "saylor:util:fx",
        "session": "eyJhcnRpY2xlSWQiOiJ1dGlsOmZ4IiwicmVmZXJlbmNlIjoiQVlZdHBjcFZoakZVM3Y0QzY0d0dxYnpqYWpGU2NUdWtqZTFLTWNQRVVucUYiLCJyZWNpcGllbnQiOiI3TFNqZnJKZjhmTnNCOFZBOXU3TjNXRW4yNXNtUUxwb2IzU3Z5VXZYYWN5NyIsIm1pbnQiOiJFUGpGV2RkNUF1ZnFTU3FlTTJxTjF4enliYXBDOEc0d0VHR2tad3lURHQxdiIsIm1pbkFtb3VudCI6MTAwMCwiZXhwIjoxNzkwMjg4MjM2NDEwfQ.IA2mGYmWhmVSn5mr5aoHtgjD1DGq2SdxJ0Sakf3GK24",
        "feePayer": "Hc3sdEAsCGQcpgfivywog9uwtk8gUBUZgsxdME1EJy88",
        "reference": "AYYtpcpVhjFU3v4C64wGqbzjajFScTukje1KMcPEUnqF"
      },
      "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
      "amount": "1000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB",
      "extra": {
        "memo": "saylor:util:fx",
        "session": "eyJhcnRpY2xlSWQiOiJ1dGlsOmZ4IiwicmVmZXJlbmNlIjoiMzlwWWdaamVHN2dTdnJzYmpGRU12OWlaNmZmM0Q3Uzd1dUdOckQ1Y04xZjEiLCJyZWNpcGllbnQiOiI3TFNqZnJKZjhmTnNCOFZBOXU3TjNXRW4yNXNtUUxwb2IzU3Z5VXZYYWN5NyIsIm1pbnQiOiJFczl2TUZyemFDRVJtSmZyRjRIMkZZRDRLQ29Oa1kxMU1jQ2U4QmVud05ZQiIsIm1pbkFtb3VudCI6MTAwMCwiZXhwIjoxNzkwMjg4MjM2NDEwfQ.bv6iG8TjHOPOzLwMXeutPnFiTvvye3diN6OOXWYUd9w",
        "feePayer": "Hc3sdEAsCGQcpgfivywog9uwtk8gUBUZgsxdME1EJy88",
        "reference": "39pYgZjeG7gSvrsbjFEMv9iZ6ff3D7S7uuGNrD5cN1f1"
      },
      "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
      "amount": "1000",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "memo": "saylor:util:fx",
        "name": "USD Coin",
        "note": "Base settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
        "version": "2",
        "facilitatorOnly": true,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xf8A376eBF123D7252cd7b66bcD77A727a4def22f",
      "amount": "1000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
      "extra": {
        "memo": "saylor:util:fx",
        "name": "USD Coin",
        "note": "Polygon settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
        "version": "2",
        "facilitatorOnly": true,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xf8A376eBF123D7252cd7b66bcD77A727a4def22f",
      "amount": "1000",
      "scheme": "exact",
      "network": "eip155:137",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
      "extra": {
        "memo": "saylor:util:fx",
        "name": "USD Coin",
        "note": "Arbitrum settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
        "version": "2",
        "facilitatorOnly": true,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xf8A376eBF123D7252cd7b66bcD77A727a4def22f",
      "amount": "1000",
      "scheme": "exact",
      "network": "eip155:42161",
      "maxTimeoutSeconds": 120
    },
    {
      "asset": "So11111111111111111111111111111111111111112",
      "extra": {
        "memo": "saylor:util:fx",
        "note": "Native SOL: send lamports with a system transfer, not an SPL transfer. Price is quoted live and this quote expires in 120s.",
        "native": true,
        "session": "eyJhcnRpY2xlSWQiOiJ1dGlsOmZ4IiwicmVmZXJlbmNlIjoiNXB5UER0OUVQNkxqUnN0akczREFrZ1VGOVltd1gzWUc1TGZtTkFTMm9kd1giLCJyZWNpcGllbnQiOiI3TFNqZnJKZjhmTnNCOFZBOXU3TjNXRW4yNXNtUUxwb2IzU3Z5VXZYYWN5NyIsIm1pbnQiOm51bGwsIm1pbkFtb3VudCI6ODMxOSwiZXhwIjoxNzkwMjg4MjM2NDEwfQ.RdpgfFhfhzkWOF1DPkjCcXC_GfZxGV9tIpTeTyEjq1A",
        "reference": "5pyPDt9EP6LjRstjG3DAkgUF9YmwX3YG5LfmNAS2odwX",
        "solUsdPrice": 116.58,
        "quotedLamports": "8577"
      },
      "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
      "amount": "8319",
      "scheme": "exact",
      "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
      "maxTimeoutSeconds": 120
    }
  ],
  "resource": {
    "url": "https://saylorinnovations.com/api/util/fx?amount=100&from=USD&to=EUR%2CJPY%2CGBP",
    "tags": [
      "utility",
      "fx"
    ],
    "iconUrl": "https://saylorinnovations.com/og-image.jpg",
    "mimeType": "application/json",
    "description": "Currency conversion (ECB reference rates, today or any date since 1999) — Real-world Data",
    "serviceName": "Saylor Innovations Real-World Utilities"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "to": "EUR,JPY,GBP",
            "from": "USD",
            "amount": "100"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "date": "2026-09-24",
            "from": "USD",
            "rates": {
              "EUR": 0.87974
            },
            "amount": 100,
            "converted": {
              "EUR": 87.974
            }
          }
        }
      },
      "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",
                  "POST",
                  "PUT",
                  "PATCH",
                  "DELETE",
                  "HEAD"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "properties": {
                  "to": {
                    "type": "string",
                    "description": "optional ISO currency or comma list, e.g. EUR,JPY (query)"
                  },
                  "from": {
                    "type": "string",
                    "description": "ISO currency, e.g. USD (query)"
                  },
                  "amount": {
                    "type": "string",
                    "description": "optional, default 1 (query)"
                  }
                }
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "json"
              },
              "example": {
                "type": "object",
                "required": [
                  "from",
                  "rates"
                ],
                "properties": {
                  "date": {
                    "type": "string"
                  },
                  "from": {
                    "type": "string"
                  },
                  "rates": {
                    "type": "object"
                  },
                  "amount": {
                    "type": [
                      "number",
                      "null"
                    ]
                  },
                  "converted": {
                    "type": "object"
                  }
                }
              }
            }
          }
        }
      }
    },
    "method": "GET",
    "example": {
      "date": "2026-09-24",
      "from": "USD",
      "rates": {
        "EUR": 0.87974
      },
      "amount": 100,
      "converted": {
        "EUR": 87.974
      }
    },
    "license": "LicenseRef-Saylor-Agent-Use-1.0",
    "mimeType": "application/json",
    "freshness": "live",
    "freeSample": "https://saylorinnovations.com/api/util/sample/fx",
    "tokenCount": null,
    "inputSchema": {
      "to": "optional ISO currency or comma list, e.g. EUR,JPY (query)",
      "date": "optional YYYY-MM-DD for a historical rate (query)",
      "from": "ISO currency, e.g. USD (query)",
      "amount": "optional, default 1 (query)"
    },
    "serviceName": "Saylor Innovations Real-World Utilities",
    "instructions": "STANDARD PATH (works with stock x402 clients): send payload.transaction — a base64 partially-signed Solana transaction — and we route verify/settle through an x402 facilitator that sponsors the fee and submits it. Include the chosen accepts entry as \"accepted\" so we can match terms. ALTERNATIVE PATH (no facilitator): Pick ONE entry from accepts and use the reference and session from THAT entry — each asset has its own. USDC or USDT: send an SPL transfer of the exact amount. Native SOL (asset=So11111111111111111111111111111111111111112, extra.native=true): send that many lamports with a system transfer. Either way include extra.reference as a read-only account (Solana Pay style), then retry with PAYMENT-SIGNATURE: base64({x402Version:2, payload:{session, reference}}). If your client cannot attach a reference, send payload.signature instead (USDC only). SOL amounts are quoted live and expire in 120s; stablecoins do not move. The facilitator path verifies and settles in this request. Only the alternative self-submitted Solana path needs retries while the transfer is indexed (typically 3-4 attempts over 10-20s). On that path, a 402 saying \"payment not found on-chain yet\" means keep retrying.",
    "outputSchema": {
      "type": "object",
      "required": [
        "from",
        "rates"
      ],
      "properties": {
        "date": {
          "type": "string"
        },
        "from": {
          "type": "string"
        },
        "rates": {
          "type": "object"
        },
        "amount": {
          "type": [
            "number",
            "null"
          ]
        },
        "converted": {
          "type": "object"
        }
      }
    },
    "settlementModes": [
      "facilitator-transaction",
      "self-submitted-reference"
    ],
    "typicalLatencyMs": 400
  },
  "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.

1000units
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.

Paid to
7LSjfr…Xacy7
Token contract
EPjFWd…TDt1v
Payment window
2 minutes
1000units
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.

Paid to
7LSjfr…Xacy7
Token contract
Es9vMF…nwNYB
Payment window
2 minutes
0.001USDC≈ $0.001 USD
on Base · exact scheme

Pay 0.001 USDC on Base to 0xf8A3…ef22f. The signed payment is good for 2 minutes.

Paid to
0xf8A3…ef22f
USD Coin contract
0x8335…02913
Payment window
2 minutes
As published
1000 smallest units
1000units
on Polygon · 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.

Paid to
0xf8A3…ef22f
Token contract
0x3c49…c3359
Payment window
2 minutes
1000units
on Arbitrum · 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.

Paid to
0xf8A3…ef22f
Token contract
0xaf88…e5831
Payment window
2 minutes
8312units
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.

Paid to
7LSjfr…Xacy7
Token contract
So1111…11112
Payment window
2 minutes
The catalog’s raw entry
[
  {
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "extra": {
      "memo": "saylor:util:fx",
      "session": "eyJhcnRpY2xlSWQiOiJ1dGlsOmZ4IiwicmVmZXJlbmNlIjoiOG1OemtONlVuemZZM0ZxYVpTRjk4UDlLN3dlVzVGRDhhcHhoOWl2YVdpQkEiLCJyZWNpcGllbnQiOiI3TFNqZnJKZjhmTnNCOFZBOXU3TjNXRW4yNXNtUUxwb2IzU3Z5VXZYYWN5NyIsIm1pbnQiOiJFUGpGV2RkNUF1ZnFTU3FlTTJxTjF4enliYXBDOEc0d0VHR2tad3lURHQxdiIsIm1pbkFtb3VudCI6MTAwMCwiZXhwIjoxNzkwMjg0Nzc2OTUzfQ.BSb5iq-72wZKzjoR89_sUuvml0Sa1D4KlwO50FD0uak",
      "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb",
      "reference": "8mNzkN6UnzfY3FqaZSF98P9K7weW5FD8apxh9ivaWiBA"
    },
    "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
    "amount": "1000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 120
  },
  {
    "asset": "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB",
    "extra": {
      "memo": "saylor:util:fx",
      "session": "eyJhcnRpY2xlSWQiOiJ1dGlsOmZ4IiwicmVmZXJlbmNlIjoiMzJXSFVZOXhheUNnbmlVTUtDZ1JobjJpTWV0V0xvQTZldWR3OFk1UVg1Z0EiLCJyZWNpcGllbnQiOiI3TFNqZnJKZjhmTnNCOFZBOXU3TjNXRW4yNXNtUUxwb2IzU3Z5VXZYYWN5NyIsIm1pbnQiOiJFczl2TUZyemFDRVJtSmZyRjRIMkZZRDRLQ29Oa1kxMU1jQ2U4QmVud05ZQiIsIm1pbkFtb3VudCI6MTAwMCwiZXhwIjoxNzkwMjg0Nzc2OTUzfQ.gLhQSeI1D-s1n7_k5UCaxn8wuJ5NJh36uTqusa3P2H0",
      "feePayer": "GVJJ7rdGiXr5xaYbRwRbjfaJL7fmwRygFi1H6aGqDveb",
      "reference": "32WHUY9xayCgniUMKCgRhn2iMetWLoA6eudw8Y5QX5gA"
    },
    "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
    "amount": "1000",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 120
  },
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "memo": "saylor:util:fx",
      "name": "USD Coin",
      "note": "Base settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
      "version": "2",
      "facilitatorOnly": true,
      "assetTransferMethod": "eip3009"
    },
    "payTo": "0xf8A376eBF123D7252cd7b66bcD77A727a4def22f",
    "amount": "1000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 120
  },
  {
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "extra": {
      "memo": "saylor:util:fx",
      "name": "USD Coin",
      "note": "Polygon settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
      "version": "2",
      "facilitatorOnly": true,
      "assetTransferMethod": "eip3009"
    },
    "payTo": "0xf8A376eBF123D7252cd7b66bcD77A727a4def22f",
    "amount": "1000",
    "scheme": "exact",
    "network": "eip155:137",
    "maxTimeoutSeconds": 120
  },
  {
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "extra": {
      "memo": "saylor:util:fx",
      "name": "USD Coin",
      "note": "Arbitrum settles through an x402 facilitator. Send payload.signature and payload.authorization (EIP-3009); there is no self-submitted path on this network.",
      "version": "2",
      "facilitatorOnly": true,
      "assetTransferMethod": "eip3009"
    },
    "payTo": "0xf8A376eBF123D7252cd7b66bcD77A727a4def22f",
    "amount": "1000",
    "scheme": "exact",
    "network": "eip155:42161",
    "maxTimeoutSeconds": 120
  },
  {
    "asset": "So11111111111111111111111111111111111111112",
    "extra": {
      "memo": "saylor:util:fx",
      "note": "Native SOL: send lamports with a system transfer, not an SPL transfer. Price is quoted live and this quote expires in 120s.",
      "native": true,
      "session": "eyJhcnRpY2xlSWQiOiJ1dGlsOmZ4IiwicmVmZXJlbmNlIjoiR1Q1Q2RrNEZpNk5QM202SHd2WDgzUHFwVktOckRzdWdyc0pVWWFvVlJhaTEiLCJyZWNpcGllbnQiOiI3TFNqZnJKZjhmTnNCOFZBOXU3TjNXRW4yNXNtUUxwb2IzU3Z5VXZYYWN5NyIsIm1pbnQiOm51bGwsIm1pbkFtb3VudCI6ODMxMiwiZXhwIjoxNzkwMjg0Nzc2OTUzfQ.ES1SlhFb7wy8VQ9HzH9iaVvQ-1wbKr_VSCbeEtkx5nQ",
      "reference": "GT5Cdk4Fi6NP3m6HwvX83PqpVKNrDsugrsJUYaoVRai1",
      "solUsdPrice": 116.68,
      "quotedLamports": "8570"
    },
    "payTo": "7LSjfrJf8fNsB8VA9u7N3WEn25smQLpob3SvyUvXacy7",
    "amount": "8312",
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "maxTimeoutSeconds": 120
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {
          "to": "EUR,JPY,GBP",
          "from": "USD",
          "amount": "100"
        }
      },
      "output": {
        "type": "json",
        "example": {
          "date": "2026-09-24",
          "from": "USD",
          "rates": {
            "EUR": 0.87974
          },
          "amount": 100,
          "converted": {
            "EUR": 87.974
          }
        }
      }
    },
    "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",
                "POST",
                "PUT",
                "PATCH",
                "DELETE",
                "HEAD"
              ],
              "type": "string"
            },
            "queryParams": {
              "type": "object",
              "properties": {
                "to": {
                  "type": "string",
                  "description": "optional ISO currency or comma list, e.g. EUR,JPY (query)"
                },
                "from": {
                  "type": "string",
                  "description": "ISO currency, e.g. USD (query)"
                },
                "amount": {
                  "type": "string",
                  "description": "optional, default 1 (query)"
                }
              }
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string",
              "const": "json"
            },
            "example": {
              "type": "object",
              "required": [
                "from",
                "rates"
              ],
              "properties": {
                "date": {
                  "type": "string"
                },
                "from": {
                  "type": "string"
                },
                "rates": {
                  "type": "object"
                },
                "amount": {
                  "type": [
                    "number",
                    "null"
                  ]
                },
                "converted": {
                  "type": "object"
                }
              }
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog
2026-09-24 21:17Z
Last indexed by Roundhouse
2026-09-25 11:50Z
Last enriched (probe, favicon, geo)
2026-09-24 22:15Z
x402 version
2
Max timeout
120s
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

Nothing indexed for this service or its provider yet. Not a claim that it is unused — only that we hold no record. 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 saylorinnovations.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=saylorinnovations.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://saylorinnovations.com/api/util/fx, 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. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402,
or use an organization key from https://roundhouseai.io/dashboard/team.

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