# Quant Agent Shop Page Change Check

> Quant Agent Shop Page Change Check is a paid API for AI agents from quantagentshop.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-23).

Checks whether the main text content of a public web page has changed since a previous check by comparing SHA-256 hashes

## Facts

- Endpoint: POST https://quantagentshop.com/v1/page-change?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quant-agent-shop-page-change-check-ddf2bcb8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ilFJ-ZE5lOIlXTnyXoB1a

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability quant-agent-shop-page-change-check-ddf2bcb8 -d '<json body>'
```

Example prompt: Check if the page at https://example.gov/announcements has changed since my last check — the previous hash was a3f1b2c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2.

## When to prefer this

Use this endpoint when you need a lightweight, stateless way to poll a public web page for text changes without storing anything server-side. It is ideal for periodic monitoring workflows where you maintain your own hash state and want a cheap ($0.002/call), fast (<2s) signal on whether content changed. Prefer this over full-page fetching (/v1/fetch-page) when you only need a yes/no change signal and don't need the actual content. Best for pages where text content changes matter (news, policy, pricing, changelogs) rather than purely visual or JavaScript-rendered changes.

## Known failure modes

- URL is not publicly accessible or returns non-200 status — returns an error, not charged
- URL points to non-HTML content or a page that blocks scraping — may return an error or unexpected hash
- Rate limit exceeded (>10 checks per host per minute) — request rejected
- Malformed URL or URL fails schema validation — validation error returned
- Transient network error fetching the target page — error returned, call not charged

## How this service works

Page change check. Send a public URL and, optionally, the hash from your last check; returns the SHA-256 of the page's main text (scripts, navigation and spacing ignored) and changed true or false. Nothing is stored here; keep the hash yourself. Use to watch a page cheaply, up to 10 checks of a host a minute. Dates or counters in the text count as changes. To read the page use /v1/fetch-page. Typical response under 2 s. Failed calls are not charged.

## Output

Returns a JSON object containing the SHA-256 hash of the page's main text content (with scripts, navigation, and whitespace noise stripped) and a boolean 'changed' field indicating whether the current hash differs from the provided previous hash. If no previous hash is supplied, 'changed' is not meaningful but the hash is returned for future comparisons. The caller must store the hash themselves — nothing is persisted server-side.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "title": "Url",
       "format": "uri",
       "maxLength": 2083,
       "minLength": 1,
       "description": "Public http or https page to hash."
      },
      "previous_sha256": {
       "anyOf": [
        {
         "type": "string",
         "pattern": "^[0-9a-fA-F]{64}$"
        },
        {
         "type": "null"
        }
       ],
       "title": "Previous Sha256",
       "default": null,
       "description": "The sha256 from your last check, to compare against."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quant-agent-shop-page-change-check-ddf2bcb8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from quantagentshop.com](https://www.zero.xyz/host/quantagentshop.com/llms.txt)