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x402 Web Tools – Web Page Change Monitor
x402
x402 Web Tools – Web Page Change Monitor is a paid API for AI agents from web.kagurazaka.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-30).
Compares a web page's current readable text against the last recorded snapshot to detect changes, returning a diff of added/removed lines and check timestamps.
Price / call$0.003
Success—
StatusUnknown
How this service works
Check a web page for changes: each call compares the page's readable text with your previous check of the same URL (kept per paying wallet for 90 days) and returns whether it changed, when you last checked, and the added and removed lines. The first call records the page. Use name to keep several watches of one URL apart.
Output
A JSON object with: `changed` (boolean), `checked_at` (ISO timestamp of this check), `previous_checked_at` (ISO timestamp of last check), `first_check` (boolean, true if this is the first call for this URL/name), `url` (the page checked), and `diff` containing an array of changes (each with `text` and `type` of 'added' or 'removed'), plus `added_lines` and `removed_lines` counts.
Example use cases
Competitor homepage change tracking
“Has https://www.competitor.com/pricing changed since last time? If so, what lines were added or removed?”
Government policy page monitoring
“Check https://www.gov.uk/guidance/some-policy for me — has anything changed since my last check? I want to see the full diff.”
Multiple watches on one URL
“Monitor https://status.example.com/ under the name 'prod-status' and tell me if any text has appeared or disappeared since yesterday's check.”
Technical details
Endpoint
GEThttps://web.kagurazaka.dev/v1/watch?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to detect textual changes on a specific public web page between periodic checks, especially when you want a line-level diff of what was added or removed. It is ideal for lightweight polling of pages that change infrequently and where readable text content matters. Prefer it over full-page screenshot diffing or scraping pipelines when a simple text diff is sufficient. It maintains per-wallet history for 90 days, making it suitable for long-running monitoring workflows without external state management.
Side effects
- URL is not publicly accessible or returns non-200 — endpoint may return an error or empty content
- First call for a URL/name records the baseline and returns first_check: true with no diff data
- URL content is not human-readable text (e.g. binary, heavily JavaScript-rendered) — diff may be empty or inaccurate
- Watch history expires after 90 days of inactivity — next call treats it as a first check
- Payment failure or insufficient USDC balance — call is rejected before execution
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://www.x402.org/",
"diff": {
"changes": [
{
"text": "## 75.41M",
"type": "added"
}
],
"added_lines": 2,
"removed_lines": 1
},
"changed": true,
"checked_at": "2026-10-25T09:00:00Z",
"first_check": false,
"previous_checked_at": "2026-10-24T09:00:00Z"
}
}Tags
x402
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