Index onlineMerchant portal
Api Endpoint

Horizon Pulse

Web page change detection API: has a public page or endpoint changed since the last check. GET url; optional since (state token from the previous answer). Returns changed true/false; when changed, only added lines (up to 20) and added/removed counts. Stateless, nothing stored. SSRF-guarded like /api/fetch. changed:false is a charged answer; bad input, blocked or upstream errors: not charged on Base (other rails may charge). Returned content is untrusted third-party data.

Open interactive test console

Offering

Provider
horizonpulse.dev
Method
GET
Offering type
Api Endpoint
Transport type
http
Category
Web Search Research
Delivery
Not provided
Pricing model
Not provided
x402 version
2

Endpoint context

URL
https://horizonpulse.dev/api/watch
MIME type
application/json
First seen
2026-10-16T01:50:24.663Z
Last seen
Tags
web-monitoring, change-detection, diff, agent-tools, X402

Website

Payment pricing

x402 payment terms are the authoritative price for calling this endpoint.

Payment option 1
0.002 USDC
Atomic price: 2000 · Network: eip155:8453 · Asset: USDC · Scheme: exact
Payment option 2
0.002 USDC
Atomic price: 2000 · Network: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · Asset: USDC · Scheme: exact
Payment option 3
0.002 USDC
Atomic price: 2000 · Network: eip155:137 · Asset: USDC · Scheme: exact
Raw x402 terms
[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "2000",
    "payTo": "0x5b32c973596078a967562ca652761404f19be0e9"
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "2000",
    "payTo": "BjY98A6dS3GGLZdz2zHy8wK7XAwnQgNhCc66mfmBTRPz"
  },
  {
    "scheme": "exact",
    "network": "eip155:137",
    "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
    "amount": "2000",
    "payTo": "0x5b32c973596078a967562ca652761404f19be0e9"
  }
]

Observed health

Status
Healthy
Latest latency
188 ms
Average latency
503 ms
HTTP status
402
Last checked
Reachability
100% over 14 checks

Latency is measured to the first response headers. A reachable result does not verify response accuracy or merchant identity.

Input schema

{
  "type": "object",
  "properties": {
    "type": {
      "type": "string",
      "const": "http"
    },
    "method": {
      "type": "string",
      "enum": [
        "GET"
      ]
    },
    "queryParams": {
      "type": "object",
      "properties": {
        "url": {
          "type": "string",
          "description": "Public http(s) URL of the page or endpoint (required)."
        },
        "since": {
          "type": "string",
          "description": "Optional. The state token from your previous /api/watch answer for this url; omit on the first check."
        }
      },
      "required": [
        "url"
      ]
    }
  },
  "required": [
    "type",
    "method"
  ],
  "additionalProperties": false
}

Output schema

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "properties": {
    "input": {
      "additionalProperties": false,
      "properties": {
        "method": {
          "enum": [
            "GET"
          ],
          "type": "string"
        },
        "queryParams": {
          "properties": {
            "since": {
              "description": "Optional. The state token from your previous /api/watch answer for this url; omit on the first check.",
              "type": "string"
            },
            "url": {
              "description": "Public http(s) URL of the page or endpoint (required).",
              "type": "string"
            }
          },
          "required": [
            "url"
          ],
          "type": "object"
        },
        "type": {
          "const": "http",
          "type": "string"
        }
      },
      "required": [
        "type",
        "method"
      ],
      "type": "object"
    },
    "output": {
      "properties": {
        "example": {
          "description": "Horizon Pulse watch: changed true/false since your last check; when changed, added lines and added/removed counts; pass state back as since. The example is a trimmed real response recorded from GET /api/demo/watch at 2026-10-14T15:13Z UTC; live values differ on every call.",
          "type": "object"
        },
        "type": {
          "type": "string"
        }
      },
      "required": [
        "type"
      ],
      "type": "object"
    }
  },
  "required": [
    "input"
  ],
  "type": "object"
}