Payments · x402 · early usage

Ask a question and get a written answer with the sources it was drawn from

Ask a question and get a written answer with the sources it was drawn from. Exa searches its index, reads the pages and composes the answer, returning the citation list (title, URL, published date) alongside it so every claim can be checked. Model-backed: the…

by agent402.tools · discovered, not yet claimed by its owner · updated 2026-10-08

30d calls3

30d payers2

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

Tags: web · search · exa · answer · citations · bazaar · builder-code · payment-identifier

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-08

Input example from Bazaar metadata

{
  "query": "What is the x402 payment protocol and who uses it?"
}

Output example

{
  "answer": "x402 is an HTTP-native payment protocol that settles stablecoin payments per request ...",
  "citationCount": 1,
  "citations": [
    {
      "author": null,
      "publishedDate": "2026-08-02T00:00:00.000Z",
      "text": null,
      "title": "What is the x402 payment protocol?",
      "url": "https://example.com/x402-explained"
    }
  ],
  "fetchedAt": "2026-09-13T20:00:00.000Z",
  "query": "What is the x402 payment protocol and who uses it?",
  "source": "exa"
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/27991.json for the price and payment options.
Pay. Call GET https://agent402.tools/api/exa-answer. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
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, eip155:143, Avalanche, eip155:1329, Optimism, eip155:4663, eip155:42220, Solana, stellar:pubnet, algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=, 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, eip155:143, Avalanche, eip155:1329, Optimism, eip155:4663, eip155:42220, Solana, stellar:pubnet, algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=
Demand: 3 calls · 2 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.01	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Polygon eip155:137	USDC	$0.01	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Arbitrum One eip155:42161	USDC	$0.01	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:143 eip155:143	0x754704Bc059F8C67012fEd69BC8A327a5aafb603	10000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Avalanche eip155:43114	0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E	10000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:1329 eip155:1329	0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392	10000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Optimism eip155:10	0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85	11000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:4663 eip155:4663	0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168	10000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	eip155:42220 eip155:42220	0xcebA9300f2b948710d2653dD7B07f33A8B32118C	10000	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
upto	Base eip155:8453	USDC	$0.01	0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0	300s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDC	$0.01	J7aN3PLJnTCF5qpEnvJHJsnCjcGuqC2rYtEM8Gv3xwg	300s
exact	stellar:pubnet stellar:pubnet	CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75	100000	GDNJXCKW7ZM7GEEVP674TWPU26YJNBQ2FI4ZIPRKTPTNUEJMDHFJWWRL	300s
exact	algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8= algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=	31566704	10000	C7IIHG7SPLPZ5H7ZT6HW3UV2OQMQQE6Y2HBNGZXSLRJULE42BEE2OY2XIE	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:143",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x754704Bc059F8C67012fEd69BC8A327a5aafb603",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:43114",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:1329",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:10",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
    "amount": "11000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:4663",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42220",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0xcebA9300f2b948710d2653dD7B07f33A8B32118C",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "upto",
    "network": "eip155:8453",
    "payTo": "0xaBF4FAbd7c416fB67202E5f9002389Fc75e2a9D0",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "J7aN3PLJnTCF5qpEnvJHJsnCjcGuqC2rYtEM8Gv3xwg",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "10000",
    "amountUsd": 0.01,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "stellar:pubnet",
    "payTo": "GDNJXCKW7ZM7GEEVP674TWPU26YJNBQ2FI4ZIPRKTPTNUEJMDHFJWWRL",
    "asset": "CCW67TSZV3SSS2HXMBQ5JFGCKJNXKZM7UQUWUZPUTHXSTZLEO7SJMI75",
    "amount": "100000",
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "algorand:wGHE2Pwdvd7S12BL5FaOP20EGYesN73ktiC1qzkkit8=",
    "payTo": "C7IIHG7SPLPZ5H7ZT6HW3UV2OQMQQE6Y2HBNGZXSLRJULE42BEE2OY2XIE",
    "asset": "31566704",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "properties": {
        "answer": {
          "type": "string"
        },
        "citationCount": {
          "type": "integer"
        },
        "citations": {
          "items": {
            "properties": {
              "author": {},
              "publishedDate": {
                "type": "string"
              },
              "text": {},
              "title": {
                "type": "string"
              },
              "url": {
                "type": "string"
              }
            },
            "type": "object"
          },
          "type": "array"
        },
        "fetchedAt": {
          "type": "string"
        },
        "query": {
          "type": "string"
        },
        "source": {
          "type": "string"
        }
      },
      "required": [
        "source",
        "fetchedAt",
        "query",
        "answer",
        "citationCount",
        "citations"
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {
    "answer": "string",
    "citationCount": 0,
    "citations": [
      {
        "author": null,
        "publishedDate": "string",
        "text": null,
        "title": "string",
        "url": "string"
      }
    ],
    "fetchedAt": "string",
    "query": "string",
    "source": "string"
  },
  "type": "string"
}

Examples

curl

curl "https://agent402.tools/api/exa-answer"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://agent402.tools/api/exa-answer");
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
res = httpx.get("https://agent402.tools/api/exa-answer")
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: agent402.tools
Endpoint: https://agent402.tools/api/exa-answer
Machine-readable: /resources/27991.json