# is-email-hosted-by-postmark

> is-email-hosted-by-postmark 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 Postmark by resolving its MX records via Cloudflare DoH and matching them against known Postmark mail-exchanger patterns.

## Facts

- Endpoint: GET https://email.intel.rallylive.ca/email/hosted-by/postmark?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-postmark-99b6f78f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1OJi19IQ7pVAwTacWsgcD

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-postmark-99b6f78f
```

Example prompt: Can you check if acmecorp.com has its email hosted by Postmark? I want to know if they're using it as their email provider.

## When to prefer this

Use this endpoint when you need to programmatically determine if a specific domain routes its email through Postmark, particularly for sales prospecting, deliverability audits, or pre-migration analysis. Prefer this over generic MX lookup tools when you specifically need Postmark provider detection with pattern matching built in. Use the bulk sibling endpoint if checking more than one domain at a time.

## Known failure modes

- Domain does not exist or has no MX records — returns no match with empty host list
- Cloudflare DoH lookup fails due to network timeout — request error returned
- Domain provided is malformed or missing — validation error
- MX records exist but do not match any Postmark pattern — returns 'no' with MX hosts listed

## How this service works

Is the domain's email hosted by postmark? Looks up the MX records (Cloudflare DoH) and matches them against postmark'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 answer indicating whether the domain's email is hosted by Postmark, along with the full list of resolved MX hosts and which specific hosts matched Postmark'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-postmark-99b6f78f/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)