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is-email-hosted-by-fastmail
x402
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.
Price / call$0.01
Success—
StatusUnknown
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.
Example use cases
Sales prospecting email provider detection
“Before I reach out to leads on my list, check if 'notionhq.com' is using Fastmail to host their email — I want to tailor my outreach based on their email infrastructure.”
Pre-migration email host verification
“We're planning to migrate a client's email away from Fastmail. Can you confirm whether 'designstudio.io' currently has its email hosted by Fastmail by checking its MX records?”
Deliverability research for a domain
“I'm doing deliverability research — can you tell me if 'indie-hacker-blog.com' uses Fastmail as its email host and show me which MX records matched?”
Technical details
Endpoint
GEThttps://email.intel.rallylive.ca/email/hosted-by/fastmail?utm_source=zero.xyzWhen to prefer
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.
Side effects
- 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
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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