# extract-h4-as-json-watch

> extract-h4-as-json-watch is a paid API for AI agents from page.intel.rallylive.ca, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-23).

Monitors a web page's H4 headings for changes, returning current H4 JSON, a changed flag, before/after diffs, and last-seen timestamp

## Facts

- Endpoint: GET https://page.intel.rallylive.ca/watch/page/h4/json?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/extract-h4-as-json-watch-e92a121c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NXO7YSi5u8RUlGlc7zBgd

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 extract-h4-as-json-watch-e92a121c
```

Example prompt: Keep an eye on https://example.com and let me know whenever its H4 headings change — I want to see what changed, what the old and new values were, and when it was last the same.

## When to prefer this

Choose this endpoint when you need to detect changes to H4-level headings specifically on a web page over time, rather than doing a one-shot extraction. It is ideal for scheduled polling workflows where you want to be alerted only when content changes, with structured before/after diffs. Prefer it over the plain extract-h4-as-json endpoint when change detection and historical comparison matter, not just current content retrieval.

## Known failure modes

- Target URL is unreachable or returns a non-200 status — check may return an error or empty H4 array
- No previous result stored for the URL (first call) — 'changed' may be undefined or false with no diff
- H4 headings are dynamically injected via JavaScript and not present in static HTML — extraction may return empty
- URL history older than 90 days is purged — baseline comparison may be unavailable
- Payment failure at $0.02 USDC — call is rejected before execution

## How this service works

Change watch for extract h4 as json: runs the check, compares it with the result from your previous call for the same url (kept 90 days) and returns the current answer, changed true/false, the fields that changed with before/after values, and when it was last seen. Schedule it to be alerted when this changes. $0.02 per check.

## Output

Returns the current H4 headings extracted from the target page as a JSON array, a boolean 'changed' flag indicating whether anything differs from the previous call for that URL, a list of fields that changed with their before and after values, and a timestamp of when the page was last seen in its prior state. Results are compared against a 90-day history per URL.

## 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",
     "properties": {}
    }
   },
   "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/extract-h4-as-json-watch-e92a121c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from page.intel.rallylive.ca](https://www.zero.xyz/host/page.intel.rallylive.ca/llms.txt)