Agent Service · x402 · early usage

Website change monitoring for agents that check in a loop: send a URL and get only what…

by agentsvc.io · discovered, not yet claimed by its owner · updated 2026-10-11

30d calls5

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

Website change monitoring for agents that check in a loop: send a URL and get only what changed since your last call (added and removed lines of the page text), plus optional keyword alerts. First call saves a baseline and returns a cursor; pass the cursor on the next call. The cursor only advances when a change is reported, so nothing slips through between polls. Good for price pages, docs and changelogs, job boards, status pages, competitor sites, government notices.

Tags: monitoring · change-detection · website-monitor · diff · alerts · bazaar · builder-code

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-11

Input example from Bazaar metadata

{
  "keywords": [
    "3.15"
  ],
  "url": "https://www.python.org/downloads/"
}

Output example

{
  "data": {
    "changed": true,
    "checked_at": "2026-10-09T06:57:46.512Z",
    "content_hash": "8eb1656e342b8803149a57e36e6885a9",
    "cursor": "OiXuu1BiPRMC2YpW",
    "cursor_help": "Pass this cursor on your next call. It only advances when a change is reported.",
    "diff": {
      "added": [
        "![Python release cycle](https://devguide.python.org/_static/release-cycle.svg)"
      ],
      "added_count": 1,
      "removed": [],
      "removed_count": 0,
      "truncated": false
    },
    "first_check": false,
    "http_status": 200,
    "keyword_alert": false,
    "keywords": [
      {
        "keyword": "3.15",
        "newly_appeared": false,
        "present": true
      }
    ],
    "line_count": 346,
    "since": "2026-10-09T06:57:46.355Z",
    "summary": "1 line(s) added, 0 removed since 2026-10-09T06:57:46.355Z. First new line: \"![Python release cycle](https://devguide.python.org/_static/release-cycle.svg)\"",
    "title": "Download Python | Python.org",
    "url": "https://www.python.org/downloads/",
    "word_count": 3196
  },
  "success": true
}

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/35689.json for the price and payment options.
Pay. Call GET https://agentsvc.io/api/v1/proxy/page-watch. 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, Solana, Polygon, Arbitrum One, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.003 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base, Solana, Polygon, Arbitrum One
Demand: 5 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	$0.003	0x622efA6Ceb83a5b6EdBC931332f4db68B7f74F27	300s
exact	Solana solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp	USDC	$0.003	5JzPS5qpEwUM1vTC9GG7uqvwJdHzbEwfoPHf2Ki977tg	300s
exact	Polygon eip155:137	USDC	$0.003	0x622efA6Ceb83a5b6EdBC931332f4db68B7f74F27	300s
exact	Arbitrum One eip155:42161	USDC	$0.003	0x622efA6Ceb83a5b6EdBC931332f4db68B7f74F27	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0x622efA6Ceb83a5b6EdBC931332f4db68B7f74F27",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "3000",
    "amountUsd": 0.003,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "payTo": "5JzPS5qpEwUM1vTC9GG7uqvwJdHzbEwfoPHf2Ki977tg",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "3000",
    "amountUsd": 0.003,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "payTo": "0x622efA6Ceb83a5b6EdBC931332f4db68B7f74F27",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "3000",
    "amountUsd": 0.003,
    "maxTimeoutSeconds": 300
  },
  {
    "scheme": "exact",
    "network": "eip155:42161",
    "payTo": "0x622efA6Ceb83a5b6EdBC931332f4db68B7f74F27",
    "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "3000",
    "amountUsd": 0.003,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "properties": {
        "data": {
          "properties": {
            "changed": {
              "type": "boolean"
            },
            "checked_at": {
              "type": "string"
            },
            "content_hash": {
              "type": "string"
            },
            "cursor": {
              "type": "string"
            },
            "cursor_help": {
              "type": "string"
            },
            "diff": {
              "properties": {
                "added": {
                  "items": {
                    "type": "string"
                  },
                  "type": "array"
                },
                "added_count": {
                  "type": "integer"
                },
                "removed": {
                  "type": "array"
                },
                "removed_count": {
                  "type": "integer"
                },
                "truncated": {
                  "type": "boolean"
                }
              },
              "type": "object"
            },
            "first_check": {
              "type": "boolean"
            },
            "http_status": {
              "type": "integer"
            },
            "keyword_alert": {
              "type": "boolean"
            },
            "keywords": {
              "items": {
                "properties": {
                  "keyword": {
                    "type": "string"
                  },
                  "newly_appeared": {
                    "type": "boolean"
                  },
                  "present": {
                    "type": "boolean"
                  }
                },
                "type": "object"
              },
              "type": "array"
            },
            "line_count": {
              "type": "integer"
            },
            "since": {
              "type": "string"
            },
            "summary": {
              "type": "string"
            },
            "title": {
              "type": "string"
            },
            "url": {
              "type": "string"
            },
            "word_count": {
              "type": "integer"
            }
          },
          "required": [
            "changed",
            "cursor",
            "summary",
            "diff"
          ],
          "type": "object"
        },
        "success": {
          "type": "boolean"
        }
      },
      "required": [
        "success",
        "data"
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

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

{
  "example": {
    "data": {
      "changed": true,
      "checked_at": "string",
      "content_hash": "string",
      "cursor": "string",
      "cursor_help": "string",
      "diff": {
        "added": [
          "string"
        ],
        "added_count": 0,
        "removed": [
          "value"
        ],
        "removed_count": 0,
        "truncated": true
      },
      "first_check": true,
      "http_status": 0,
      "keyword_alert": true,
      "keywords": [
        {
          "keyword": "string",
          "newly_appeared": true,
          "present": true
        }
      ],
      "line_count": 0,
      "since": "string",
      "summary": "string",
      "title": "string",
      "url": "string",
      "word_count": 0
    },
    "success": true
  },
  "type": "string"
}

Examples

curl

curl "https://agentsvc.io/api/v1/proxy/page-watch"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://agentsvc.io/api/v1/proxy/page-watch");
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://agentsvc.io/api/v1/proxy/page-watch")
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: agentsvc.io
Endpoint: https://agentsvc.io/api/v1/proxy/page-watch
Machine-readable: /resources/35689.json