# Substack.com Down Status Change Watcher

> Substack.com Down Status Change Watcher is a paid API for AI agents from monitor.intel.rallylive.ca, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-02).

Monitors substack.com availability and returns whether its status has changed since the last check, with before/after field diffs and timestamps.

## Facts

- Endpoint: GET https://monitor.intel.rallylive.ca/watch/monitor/is-down/substack-com?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/substack-com-down-status-change-watcher-1a78bde3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__hDO0vrDcSJh1jcPeYAic

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 substack-com-down-status-change-watcher-1a78bde3
```

Example prompt: Keep an eye on substack.com for me and let me know the moment its availability status changes — whether it goes down or comes back up.

## When to prefer this

Use this endpoint when you need to detect changes in substack.com's availability over time rather than just a one-time spot check. It is ideal for scheduled polling workflows where you want to be alerted only when something actually changes, avoiding noise from repeated identical results. Prefer it over a plain 'is-down' check when you need the before/after diff and change timestamp for logging or alerting pipelines.

## Known failure modes

- No previous check stored (first call returns current state only, changed=false or null)
- Network error reaching substack.com from the monitoring edge (may return timeout or error status)
- Payment failure for $0.02 USDC via x402 protocol (request rejected before check runs)
- Stale comparison if last check was older than 90-day retention window

## How this service works

Change watch for is substack com down: runs the check, compares it with the result from your previous call for the same query (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 availability answer for substack.com, a boolean 'changed' flag indicating whether the status differs from the previous call, a list of fields that changed with their before and after values, and the timestamp of when the status was last seen. Previous check results are retained for 90 days per query.

## 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/substack-com-down-status-change-watcher-1a78bde3/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from monitor.intel.rallylive.ca](https://www.zero.xyz/host/monitor.intel.rallylive.ca/llms.txt)