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POST AI agent ready /v1/email-mx/verify

Email MX Verify API - Check Deliverability by DNS

Validates the address format, extracts the domain, and queries Cloudflare DNS for MX records. Returns the sorted MX hosts with priorities plus a deliverable flag: "likely" when MX records exist, "unknown" when only an A record exists (RFC 5321 fallback), and "unlikely" when neither is present. Does not send test emails, so it does not trigger the target mail server.

Parameters

stringrequired

Full email address to verify (local-part@domain).

Code examples

curl -X POST https://api.botoi.com/v1/email-mx/verify \
  -H "Content-Type: application/json" \
  -d '{"email":"support@github.com"}'

When to use this API

Clean a marketing list before sending

Run every address on your newsletter list through this endpoint before a major send. Drop anything flagged "unlikely" to improve deliverability and avoid spam-trap bounces that hurt your sender reputation.

Inline validation on signup forms

After format validation passes, call this endpoint to catch domain typos (gmial.com, outlok.com) that MX lookups detect. Return a client-side message suggesting the correct domain before the user submits.

Qualify sales leads by mail provider

Inspect the MX records to route leads: addresses served by Google Workspace or Microsoft 365 go to the enterprise sales queue. Personal Gmail and Yahoo addresses route to self-serve onboarding.

Frequently asked questions

Does this confirm the mailbox exists?
No. This checks the domain, not the specific mailbox. A "likely" result means mail to the domain can be routed; it does not guarantee the local part is a real inbox. For mailbox-level verification you need an SMTP probe, which most providers rate-limit aggressively.
When does deliverable return "unknown"?
When the domain has no MX records but does have an A record. Per RFC 5321, mail servers should fall back to delivering via the A record host. Some domains accept mail this way; others do not.
How are MX records sorted?
By priority ascending. The lowest-priority host is the primary MX; higher numbers are fallbacks that receive mail only when the primary is unreachable.
Which DNS resolver does the endpoint use?
Cloudflare's DNS-over-HTTPS resolver (1.1.1.1) via the /dns-query endpoint. Lookups time out at 5 seconds.
Will this trigger a mail server alert?
No. MX lookups hit DNS only. No connection is made to the target mail server, so there is no SMTP log entry or rate-limit counter increment on their side.

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