Roundhouse AI

FractalAI Pay-per-Proof

The first AI-native Layer 1 blockchain built from scratch in Rust. Post-quantum cryptography (CRYSTALS-Dilithium), Proof of Fractal Work consensus, WASM smart contracts, and 460+ RPC endpoints. Mine FRAC tokens with fractal analysis instead of hash puzzles.

SocialLiveeip155:8453Exactvia cdp
https://fractalai.net.co/api/x402/sign
SignaturePost-quantumMl-dsa-65Ai-agentFips-204
Calls · 30d
2
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 9 snapshots so far.
$1.09
Verified settled volume
52 settlements proven x402 by their on-chain EIP-3009 marker.
$0.020
Listed price
As published in the catalog. Always read the live 402 before paying.
2
Calls · 30d
Upstream's own call count for this endpoint, not ours.
2
Unique payers · 30d
Last called 2026-09-15 16:22Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0xC13789e82661635d9Cea38a53A0390CF9939ef4f

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",
  "price": "$0.02",
  "usage": "POST { message | hash }. First call → 402 with `accepts` (facilitator EIP-3009 gasless, or pay-first txHash). Facilitator-native: retry with X-PAYMENT = base64(JSON(exact-scheme payload with a signed EIP-3009 authorization)). Fallback: retry with X-PAYMENT = base64(JSON({ txHash })). Returns an ML-DSA-65 / Dilithium-3 signature.",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2",
        "decimals": 6,
        "assetTransferMethod": "eip3009"
      },
      "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
      "amount": "20000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    },
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USDC",
        "decimals": 6,
        "settlement": "txHash",
        "instructions": "Facilitator-less: send exactly `amount` USDC to `payTo` on Base, then retry with PAYMENT-SIGNATURE = base64(JSON({ txHash })) (X-PAYMENT also accepted)."
      },
      "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
      "amount": "20000",
      "scheme": "exact",
      "network": "eip155:8453",
      "maxTimeoutSeconds": 300
    }
  ],
  "service": "FractalAI x402 Pay-per-Proof — post-quantum signatures for autonomous agents",
  "resource": {
    "url": "https://fractalai.net.co/api/x402/sign",
    "tags": [
      "signature",
      "post-quantum",
      "ml-dsa-65",
      "ai-agent",
      "fips-204"
    ],
    "mimeType": "application/json",
    "description": "Pay-per-Proof: one post-quantum ML-DSA-65 / Dilithium-3 (NIST FIPS 204) signature over your message/hash, x402-native.",
    "serviceName": "FractalAI Pay-per-Proof"
  },
  "extensions": {
    "bazaar": {
      "body": {
        "message": "hello agent economy"
      },
      "info": {
        "input": {
          "body": {
            "message": "hello agent economy"
          },
          "type": "http",
          "method": "POST",
          "bodyType": "json"
        },
        "output": {
          "type": "json",
          "example": {
            "digest": "9f86…",
            "algorithm": "ml-dsa-65",
            "signature": "BASE64_ML_DSA65_3309B",
            "public_key": "BASE64_ML_DSA65_1952B"
          }
        }
      },
      "tags": [
        "signature",
        "post-quantum",
        "ml-dsa-65",
        "ai-agent",
        "fips-204"
      ],
      "type": "http",
      "method": "POST",
      "output": {
        "type": "json",
        "schema": {
          "type": "object",
          "required": [
            "digest",
            "signature",
            "algorithm",
            "public_key"
          ],
          "properties": {
            "digest": {
              "type": "string",
              "description": "The hex digest that was signed."
            },
            "payment": {
              "type": "object",
              "description": "Settlement receipt (scheme, network, asset, txHash, payer, settled)."
            },
            "algorithm": {
              "type": "string",
              "description": "ml-dsa-65"
            },
            "signature": {
              "type": "string",
              "description": "Base64 ML-DSA-65 / Dilithium-3 (NIST FIPS 204) signature (3309 bytes) over FRACTALAI-x402-served-v1\\nx402-sign\\n<digest>."
            },
            "public_key": {
              "type": "string",
              "description": "Base64 ML-DSA-65 public key (1952 bytes) that verifies the signature."
            }
          }
        },
        "example": {
          "digest": "9f86…",
          "algorithm": "ml-dsa-65",
          "signature": "BASE64_ML_DSA65_3309B",
          "public_key": "BASE64_ML_DSA65_1952B"
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method",
              "bodyType",
              "body"
            ],
            "properties": {
              "body": {
                "type": "object"
              },
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "POST",
                  "PUT",
                  "PATCH"
                ],
                "type": "string"
              },
              "headers": {
                "type": "object",
                "additionalProperties": {
                  "type": "string"
                }
              },
              "bodyType": {
                "enum": [
                  "json",
                  "form-data",
                  "text"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "additionalProperties": {
                  "type": "string"
                }
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object"
              }
            }
          }
        }
      },
      "bodyType": "json",
      "route_key": "POST /api/x402/sign",
      "description": "Pay-per-Proof: one post-quantum ML-DSA-65 / Dilithium-3 (NIST FIPS 204) signature over your message/hash, x402-native.",
      "serviceName": "FractalAI Pay-per-Proof"
    }
  },
  "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.

0.02USDC≈ $0.02 USD
on Base · exact scheme

Pay 0.02 USDC on Base to 0xC137…9ef4f. The signed payment is good for 5 minutes.

Paid to
0xC137…9ef4f
USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
20000 smallest units
0.02USDC≈ $0.02 USD
on Base · exact scheme

Pay 0.02 USDC on Base to 0xC137…9ef4f. The signed payment is good for 5 minutes.

Paid to
0xC137…9ef4f
USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
20000 smallest units
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2",
      "decimals": 6,
      "assetTransferMethod": "eip3009"
    },
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "amount": "20000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  },
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USDC",
      "decimals": 6,
      "settlement": "txHash",
      "instructions": "Facilitator-less: send exactly `amount` USDC to `payTo` on Base, then retry with PAYMENT-SIGNATURE = base64(JSON({ txHash })) (X-PAYMENT also accepted)."
    },
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "amount": "20000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "body": {
      "message": "hello agent economy"
    },
    "info": {
      "input": {
        "body": {
          "message": "hello agent economy"
        },
        "type": "http",
        "method": "POST",
        "bodyType": "json"
      },
      "output": {
        "type": "json",
        "example": {
          "digest": "9f86…",
          "algorithm": "ml-dsa-65",
          "signature": "BASE64_ML_DSA65_3309B",
          "public_key": "BASE64_ML_DSA65_1952B"
        }
      }
    },
    "tags": [
      "signature",
      "post-quantum",
      "ml-dsa-65",
      "ai-agent",
      "fips-204"
    ],
    "type": "http",
    "method": "POST",
    "output": {
      "type": "json",
      "schema": {
        "type": "object",
        "required": [
          "digest",
          "signature",
          "algorithm",
          "public_key"
        ],
        "properties": {
          "digest": {
            "type": "string",
            "description": "The hex digest that was signed."
          },
          "payment": {
            "type": "object",
            "description": "Settlement receipt (scheme, network, asset, txHash, payer, settled)."
          },
          "algorithm": {
            "type": "string",
            "description": "ml-dsa-65"
          },
          "signature": {
            "type": "string",
            "description": "Base64 ML-DSA-65 / Dilithium-3 (NIST FIPS 204) signature (3309 bytes) over FRACTALAI-x402-served-v1\\nx402-sign\\n<digest>."
          },
          "public_key": {
            "type": "string",
            "description": "Base64 ML-DSA-65 public key (1952 bytes) that verifies the signature."
          }
        }
      },
      "example": {
        "digest": "9f86…",
        "algorithm": "ml-dsa-65",
        "signature": "BASE64_ML_DSA65_3309B",
        "public_key": "BASE64_ML_DSA65_1952B"
      }
    },
    "schema": {
      "type": "object",
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "required": [
        "input"
      ],
      "properties": {
        "input": {
          "type": "object",
          "required": [
            "type",
            "method",
            "bodyType",
            "body"
          ],
          "properties": {
            "body": {
              "type": "object"
            },
            "type": {
              "type": "string",
              "const": "http"
            },
            "method": {
              "enum": [
                "POST",
                "PUT",
                "PATCH"
              ],
              "type": "string"
            },
            "headers": {
              "type": "object",
              "additionalProperties": {
                "type": "string"
              }
            },
            "bodyType": {
              "enum": [
                "json",
                "form-data",
                "text"
              ],
              "type": "string"
            },
            "queryParams": {
              "type": "object",
              "additionalProperties": {
                "type": "string"
              }
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object"
            }
          }
        }
      }
    },
    "bodyType": "json",
    "route_key": "POST /api/x402/sign",
    "description": "Pay-per-Proof: one post-quantum ML-DSA-65 / Dilithium-3 (NIST FIPS 204) signature over your message/hash, x402-native.",
    "serviceName": "FractalAI Pay-per-Proof"
  }
}

Provenance

Seen in the source catalog
2026-09-15 16:22Z
Last indexed by Roundhouse
2026-09-24 21:30Z
Last enriched (probe, favicon, geo)
2026-09-15 19:45Z
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

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 9 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 FractalAI Pay-per-Proof 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=FractalAI%20Pay-per-Proof'
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://fractalai.net.co/api/x402/sign, 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.