# Is Email Hosted by Fastmail – Change Watch

> Is Email Hosted by Fastmail – Change Watch is a paid API for AI agents from email.intel.rallylive.ca, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-24).

Monitors whether a domain's email is hosted by Fastmail and alerts when that status changes, comparing current MX-record results against a stored baseline from up to 90 days ago.

## Facts

- Endpoint: GET https://email.intel.rallylive.ca/watch/email/hosted-by/fastmail?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-24
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/is-email-hosted-by-fastmail-change-watch-4be46030
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HJIPs9SS5jquk8UOzL8sg

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 is-email-hosted-by-fastmail-change-watch-4be46030
```

Example prompt: Keep watching acmecorp.com and let me know the moment it switches to or away from Fastmail for email hosting — compare it against the last result and tell me exactly what changed.

## When to prefer this

Use this watch endpoint instead of the plain check when you need change-detection semantics — i.e., you want to know not just the current Fastmail hosting status but whether it has changed since your last query. Ideal for scheduled polling workflows, alerting pipelines, or competitive intelligence where transitions matter more than point-in-time state. For one-off checks without change tracking, prefer the base is-email-hosted-by-fastmail endpoint. For checking many domains at once, use the bulk variant.

## Known failure modes

- Domain not provided or malformed — returns an input validation error
- DNS lookup failure due to Cloudflare DoH outage — may return an error or stale result
- No previous baseline exists for the domain (first call) — 'changed' will be false or undefined
- Domain has no MX records — returns false for Fastmail hosting with no diff
- Payment not included or insufficient — x402 payment required error

## How this service works

Change watch for is email hosted by fastmail: runs the check, compares it with the result from your previous call for the same domain (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 Fastmail-hosting boolean, a 'changed' true/false flag, a diff of any fields that changed with their before and after values, and a timestamp for when the status was last seen. The baseline is retained for 90 days per domain.

## 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/is-email-hosted-by-fastmail-change-watch-4be46030/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from email.intel.rallylive.ca](https://www.zero.xyz/host/email.intel.rallylive.ca/llms.txt)