# x402 Web Tools – Web Page Change Watcher

> x402 Web Tools – Web Page Change Watcher is a paid API for AI agents from q7w9tnp09rjt5ccj.68r.lambda-web.us-east-1.on.aws, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-30).

Compares a web page's current readable text against a previously stored snapshot and returns whether it changed, what was added or removed, and when it was last checked.

## Facts

- Endpoint: GET https://q7w9tnp09rjt5ccj.68r.lambda-web.us-east-1.on.aws/v1/watch?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-web-tools-web-page-change-watcher-9a41e8e1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_V5z0B6Xx-TraA3SEfVwAO

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 x402-web-tools-web-page-change-watcher-9a41e8e1
```

Example prompt: Check whether the pricing page at https://www.example.com/pricing has changed since the last time you looked — I want to know what lines were added or removed.

## When to prefer this

Choose this endpoint when you need to detect textual changes on a public web page over time, especially when you want a structured diff (added/removed lines) rather than just a notification. It maintains per-wallet snapshot history for 90 days, supports multiple named watches per URL, and costs only $0.003 USDC per call — ideal for lightweight polling in agentic workflows without managing your own storage or diffing logic.

## Known failure modes

- URL is not publicly reachable or returns an error — endpoint may return an error or empty content
- Page has no extractable readable text (e.g. pure JavaScript SPA before render) — diff may be empty or inaccurate
- First call records the baseline so no diff is available yet — first_check will be true
- Watch history expires after 90 days of inactivity — next call treated as first check
- Invalid or missing URL parameter — request fails validation
- Name parameter exceeds 64 characters — rejected by schema

## 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 containing: whether the page changed (boolean), the diff with lists of added and removed lines and their counts, the current check timestamp, the previous check timestamp, and whether this was the first check for this URL/name combination. On first call, the page is recorded and first_check is true with no diff data.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "https URL of the page"
      },
      "name": {
       "type": "string",
       "description": "optional name to keep separate watches of the same URL (up to 64 characters)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "url": {},
      "diff": {},
      "changed": {},
      "checked_at": {},
      "first_check": {},
      "previous_checked_at": {}
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "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"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-web-tools-web-page-change-watcher-9a41e8e1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from q7w9tnp09rjt5ccj.68r.lambda-web.us-east-1.on.aws](https://www.zero.xyz/host/q7w9tnp09rjt5ccj.68r.lambda-web.us-east-1.on.aws/llms.txt)