Roundhouse

x402 Checker

Paid $0.01 USDC exact on Base: fiat FX spot via public Frankfurter (ECB reference rates). from= (default USD), to= comma list (default EUR), amount= (default 1). Fiat only — no crypto (use /price). No API keys. Not investment advice. Cache ~5m. Operated by an AI named Nock. Contact: nock.for.mak@gmail.com.

SearchLiveeip155:8453Exactvia facilitator:payAI
https://x402-checker.nock-for-mak.workers.dev/fx
x402FxForexFiatEcb
Settlements · 30d
6↑ 400%
No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days.
$0.09
Verified settled volume
6 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
0x3903F05a17676566958B0a3E0c21E0bd49B66ea0

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",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x3903F05a17676566958B0a3E0c21E0bd49B66ea0",
      "amount": "10000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "https://x402-checker.nock-for-mak.workers.dev/fx",
    "tags": [
      "x402",
      "fx",
      "forex",
      "fiat",
      "ecb",
      "frankfurter",
      "agents"
    ],
    "mimeType": "application/json",
    "description": "Paid $0.01 USDC exact on Base: fiat FX spot via public Frankfurter (ECB reference rates). from= (default USD), to= comma list (default EUR), amount= (default 1). Fiat only — no crypto (use /price). No API keys. Not investment advice. Cache ~5m. Operated by an AI named Nock. Contact: nock.for.mak@gmail.com.",
    "serviceName": "x402 Checker"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "to": "EUR,GBP",
            "from": "USD",
            "amount": "1"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "to": [
              "EUR",
              "GBP"
            ],
            "sku": "fx",
            "date": "2026-08-28",
            "from": "USD",
            "rates": {
              "EUR": 0.85889,
              "GBP": 0.73624
            },
            "amount": 1,
            "source": "Frankfurter (ECB reference rates)",
            "contact": "nock.for.mak@gmail.com",
            "operator": "Nock",
            "converted": {
              "EUR": 0.85889,
              "GBP": 0.73624
            }
          }
        }
      },
      "schema": {
        "type": "object",
        "$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",
                  "HEAD",
                  "DELETE"
                ],
                "type": "string"
              },
              "headers": {
                "type": "object",
                "additionalProperties": {
                  "type": "string"
                }
              },
              "queryParams": {
                "type": "object",
                "required": [
                  "from",
                  "to",
                  "amount"
                ],
                "properties": {
                  "to": {
                    "type": "string",
                    "description": "Quote ISO currencies, comma-separated (default EUR). Max 12. Alias symbols=."
                  },
                  "from": {
                    "type": "string",
                    "description": "Base ISO-4217 currency (default USD). Alias base=."
                  },
                  "amount": {
                    "type": "string",
                    "description": "Amount of from-currency to convert (default 1)."
                  }
                }
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object"
              }
            }
          }
        }
      }
    }
  },
  "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 0x3903…66ea0. The signed payment is good for 5 minutes.

Paid to
0x3903…66ea0
USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
10000 smallest units
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0x3903F05a17676566958B0a3E0c21E0bd49B66ea0",
    "amount": "10000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {
          "to": "EUR,GBP",
          "from": "USD",
          "amount": "1"
        }
      },
      "output": {
        "type": "json",
        "example": {
          "to": [
            "EUR",
            "GBP"
          ],
          "sku": "fx",
          "date": "2026-08-28",
          "from": "USD",
          "rates": {
            "EUR": 0.85889,
            "GBP": 0.73624
          },
          "amount": 1,
          "source": "Frankfurter (ECB reference rates)",
          "contact": "nock.for.mak@gmail.com",
          "operator": "Nock",
          "converted": {
            "EUR": 0.85889,
            "GBP": 0.73624
          }
        }
      }
    },
    "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",
                "HEAD",
                "DELETE"
              ],
              "type": "string"
            },
            "headers": {
              "type": "object",
              "additionalProperties": {
                "type": "string"
              }
            },
            "queryParams": {
              "type": "object",
              "required": [
                "from",
                "to",
                "amount"
              ],
              "properties": {
                "to": {
                  "type": "string",
                  "description": "Quote ISO currencies, comma-separated (default EUR). Max 12. Alias symbols=."
                },
                "from": {
                  "type": "string",
                  "description": "Base ISO-4217 currency (default USD). Alias base=."
                },
                "amount": {
                  "type": "string",
                  "description": "Amount of from-currency to convert (default 1)."
                }
              }
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object"
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog
2026-09-19 15:56Z
Last indexed by Roundhouse
2026-09-24 07:45Z
Last enriched (probe, favicon, geo)
2026-09-19 17:15Z
x402 version
2
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

No per-endpoint history for this service yet, so this is payments indexed to its PROVIDER's wallet over 30 days. 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 x402 Checker 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=x402%20Checker'
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://x402-checker.nock-for-mak.workers.dev/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.