# is-email-hosted-by-fastmail

> is-email-hosted-by-fastmail is a paid API for AI agents from email.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).

Checks whether a domain's email is hosted by Fastmail by looking up its MX records via Cloudflare DoH and matching against Fastmail's mail-exchanger patterns.

## Facts

- Endpoint: GET https://email.intel.rallylive.ca/email/hosted-by/fastmail?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/is-email-hosted-by-fastmail-3e760a69
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oc4cNdeXU_xwauZHYdCmY

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-3e760a69
```

Example prompt: Can you check if the domain 'acmecorp.com' has its email hosted by Fastmail — I need to know whether their MX records point to Fastmail's mail exchangers.

## When to prefer this

Use this endpoint when you need a fast, single-domain check specifically for Fastmail hosting detection. It is ideal for sales intelligence, email migration planning, or deliverability research where you need to confirm Fastmail as the provider. Prefer this over generic MX lookup tools when you need a definitive yes/no answer with matched pattern details rather than raw DNS data.

## Known failure modes

- Domain does not exist or has no MX records — returns no match with empty MX list
- DNS lookup failure via Cloudflare DoH — may return an error or inconclusive result
- Domain has MX records from an unknown provider — returns no match with unmatched hosts listed
- Rate limiting or payment failure — request rejected with 402 or 429 response

## How this service works

Is the domain's email hosted by fastmail? Looks up the MX records (Cloudflare DoH) and matches them against fastmail's mail-exchanger patterns, returning yes/no, the MX hosts and which matched. Provider detection for deliverability, sales and migration work. $0.01 per lookup.

## Output

Returns a yes/no result indicating whether the domain's email is hosted by Fastmail, along with the full list of MX host records retrieved and which specific records matched Fastmail's known mail-exchanger patterns.

## 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-3e760a69/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)