catch all email detection api
Catch all email detection API
Detect domains that accept every mailbox and return less reliable deliverability signals.
Catch-all domains can make mailbox existence harder to prove.
They are common in corporate setups and can produce misleading positives.
Use them as a risk factor, not as a standalone verdict.
220 mail.example.com ESMTP
EHLO emailverify.se
MAIL FROM:<[email protected]>
RCPT TO:<[email protected]>
QUITWhy catch-all matters
A domain that accepts everything can still bounce later or route messages unpredictably.
How to treat the result
Flag the address as risky and combine the signal with score-based logic.
Why catch-all is a risk signal
Catch-all servers accept many or all local parts, so a positive response does not strongly prove mailbox existence. That makes them useful for risk scoring but weak as a yes/no proof of deliverability.
How teams should treat it
The right response is usually to downgrade confidence, not immediately reject. High-value signups can be escalated to extra review or a stronger verification path, while low-value signups can be handled more strictly.
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.
Is catch-all the same as invalid?
No. It is usually valid, just less certain.
Why does it matter for onboarding?
Because it changes how much trust you should place in the address result.