email domain validation api
Email domain validation API
Validate domains separately so you can reject broken or suspicious signups before account creation.
Domain validation is the bridge between syntax and inbox-level checks.
It helps you catch bad TLDs, missing MX records, and poisoned domains.
It is useful for enterprise forms and public signups alike.
dig MX example.com
nslookup -type=mx example.comWhat is validated?
The domain portion after the @ sign, including DNS and deliverability signals.
Why split it out?
It gives you a clearer failure reason and better UX.
How MX lookup fits into the chain
MX checks are the first deliverability gate after syntax validation. If a domain cannot publish mail exchanger records, you already have a strong reason to reject or flag the address before spending time on deeper probes.
Operational tradeoff
MX lookup is inexpensive and fast, but it does not prove mailbox ownership. The best implementation treats it as a domain health signal and combines it with disposable-domain checks, score thresholds, and a clear user message.
FAQ
How do I use this page?
Use it as a quickstart reference and link it from your docs, onboarding flow, or marketing page.
What should I do next?
Create an account, try the demo, and move the integration into your backend with a real API key.
Should I block missing MX?
Usually yes for consumer signup flows, unless you intentionally support edge cases like custom routing.
Does MX guarantee inbox delivery?
No. It only indicates where mail should be delivered; the mailbox can still be unreachable or rejected later.