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Agent Service · x402 · early usage

Pay-per-Verify: an agent pays $0.01 to verify a post-quantum (ML-DSA-65 / Dilithium-3 o…

Pay-per-Verify: an agent pays $0.01 to verify a post-quantum (ML-DSA-65 / Dilithium-3 or Dilithium-2, NIST FIPS 204; scheme auto-detected by size) signature over a message against a public key. A generic machine-to-machine PQC proof primitive for autonomous a…

by fractalai.net.co · discovered, not yet claimed by its owner · updated 2026-10-13

30d calls10
30d payers6
MethodPOST
Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Pay-per-Verify: an agent pays $0.01 to verify a post-quantum (ML-DSA-65 / Dilithium-3 or Dilithium-2, NIST FIPS 204; scheme auto-detected by size) signature over a message against a public key. A generic machine-to-machine PQC proof primitive for autonomous agents. x402-native.

Tags: verify · signature · post-quantum · primitive · ml-dsa-65 · bazaar

Call contract

Method
POST
Input
json
Output
json
Last paid call
2026-10-13
Input example from Bazaar metadata
{
  "message_b64": "BASE64_BYTES",
  "public_key": "BASE64_PK",
  "signature": "BASE64_SIG"
}
Output example
{
  "algorithm": "ml-dsa-65",
  "valid": true,
  "verified_algorithm": "dilithium2"
}

Use with an agent

  1. Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
  2. Inspect. Fetch /resources/33269.json for the price and payment options.
  3. Pay. Call GET https://fractalai.net.co/api/x402/verify-proof. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
  4. Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, Polygon, Arbitrum One, eip155:480, eip155:42220, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price
$0.01 / request
Protocol
x402 v2
Auth
No account or API key. Pay per request.
Networks
Base, Polygon, Arbitrum One, eip155:480, eip155:42220
Demand
10 calls · 6 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

SchemeNetworkAssetAmountPay toTimeout
exactBase
eip155:8453		USDC$0.010xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactBase
eip155:8453		USDC$0.010xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactPolygon
eip155:137		0x12050c705152931cFEe3DD56c52Fb09Dea816C23319500000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactBase
eip155:8453		0xF197FFC28c23E0309B5559e7a166f2c6164C80aA1826000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactArbitrum One
eip155:42161		0xF197FFC28c23E0309B5559e7a166f2c6164C80aA1826000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactPolygon
eip155:137		0xE6A537a407488807F0bbeb0038B79004f19DDDFb499000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactPolygon
eip155:137		0x4eD141110F6EeeAbA9A1df36d8c26f684d2475Dc499000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exacteip155:480
eip155:480		0x0DC4F92879B7670e5f4e4e6e3c801D229129D90D151700000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactBase
eip155:8453		0x0DC4F92879B7670e5f4e4e6e3c801D229129D90D151700000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exacteip155:480
eip155:480		0xD76f5Faf6888e24D9F04Bf92a0c8B921FE4390e0499000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactBase
eip155:8453		0xD76f5Faf6888e24D9F04Bf92a0c8B921FE4390e0499000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exacteip155:480
eip155:480		0x337E7456B420bD3481e7FA61fA9850343d610d341826000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactBase
eip155:8453		0x337E7456B420bD3481e7FA61fA9850343d610d341826000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exacteip155:480
eip155:480		0x8a1D45e102e886510e891d2Ec656a708991e2D76319500000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactBase
eip155:8453		0x8a1D45e102e886510e891d2Ec656a708991e2D76319500000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exactPolygon
eip155:137		0x55cF6b630d8AE6477DF63e194F0fd80ACFf05f86319500000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exacteip155:42220
eip155:42220		0x8A567e2aE79CA692Bd748aB832081C45de4041eA319500000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
exacteip155:42220
eip155:42220		0xe8537a3d056DA446677B9E9d6c5dB704EaAb4787499000000000000000xC13789e82661635d9Cea38a53A0390CF9939ef4f300s
accepts[] (raw JSON)
[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x12050c705152931cFEe3DD56c52Fb09Dea816C23",
    "amount": "31950000000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0xF197FFC28c23E0309B5559e7a166f2c6164C80aA",
    "amount": "182600",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0xF197FFC28c23E0309B5559e7a166f2c6164C80aA",
    "amount": "182600",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0xE6A537a407488807F0bbeb0038B79004f19DDDFb",
    "amount": "49900000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x4eD141110F6EeeAbA9A1df36d8c26f684d2475Dc",
    "amount": "49900000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:480",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x0DC4F92879B7670e5f4e4e6e3c801D229129D90D",
    "amount": "15170000000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x0DC4F92879B7670e5f4e4e6e3c801D229129D90D",
    "amount": "15170000000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:480",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0xD76f5Faf6888e24D9F04Bf92a0c8B921FE4390e0",
    "amount": "49900000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0xD76f5Faf6888e24D9F04Bf92a0c8B921FE4390e0",
    "amount": "49900000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:480",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x337E7456B420bD3481e7FA61fA9850343d610d34",
    "amount": "182600000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x337E7456B420bD3481e7FA61fA9850343d610d34",
    "amount": "182600000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:480",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x8a1D45e102e886510e891d2Ec656a708991e2D76",
    "amount": "31950000000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x8a1D45e102e886510e891d2Ec656a708991e2D76",
    "amount": "31950000000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x55cF6b630d8AE6477DF63e194F0fd80ACFf05f86",
    "amount": "31950000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42220",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0x8A567e2aE79CA692Bd748aB832081C45de4041eA",
    "amount": "31950000000000000000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42220",
    "payTo": "0xC13789e82661635d9Cea38a53A0390CF9939ef4f",
    "asset": "0xe8537a3d056DA446677B9E9d6c5dB704EaAb4787",
    "amount": "49900000000000000",
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)
{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}
Example shape — generated from the schema, not a captured live response
{
  "example": {},
  "type": "string"
}

Examples

curl
curl -X POST 'https://fractalai.net.co/api/x402/verify-proof' -H 'Content-Type: application/json' --data '{"message_b64":"BASE64_BYTES","public_key":"BASE64_PK","signature":"BASE64_SIG"}'
# -> 402 Payment Required; read PAYMENT-REQUIRED
# retry the identical request with PAYMENT-SIGNATURE
JavaScript
const res = await fetch("https://fractalai.net.co/api/x402/verify-proof", {
  "method": "POST",
  "headers": {
    "content-type": "application/json"
  },
  "body": "{\"message_b64\":\"BASE64_BYTES\",\"public_key\":\"BASE64_PK\",\"signature\":\"BASE64_SIG\"}"
});
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}
Python
import httpx
import json
res = httpx.request("POST", "https://fractalai.net.co/api/x402/verify-proof", json=json.loads("{\"message_b64\":\"BASE64_BYTES\",\"public_key\":\"BASE64_PK\",\"signature\":\"BASE64_SIG\"}"))
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider
fractalai.net.co
Endpoint
https://fractalai.net.co/api/x402/verify-proof
Machine-readable
/resources/33269.json