Explainer

Catch-all email addresses explained

Catch-all domains accept mail for any address, which makes them impossible to verify mailbox by mailbox. Here is what to do with them.

Updated October 1, 2026 · 1 min read

What is a catch-all domain?

A domain whose mail server accepts email for every address: anna@, sales@ and xk29qz@ all get a 250 OK. Companies set this up so that no mail to a misspelled colleague is lost, or simply by default in some mail systems.

Why verifiers call them “risky”

Email verification asks the server whether it accepts a recipient (see how to check if an email exists). On a catch-all domain the answer is always yes, so the check proves nothing about the individual mailbox. The mail may reach a real person, a shared catch-all inbox nobody reads, or bounce later.

How to detect a catch-all domain

Ask the server about an address that certainly does not exist, like a long random string. If it is accepted, the domain is catch-all. The email validator and the API do this automatically and return catch_all: true.

How to handle catch-all addresses

  1. Keep them separate from verified addresses.
  2. Send in small batches and watch the bounces.
  3. Prioritize engagement: remove addresses that never open or click after a few sends.
  4. Use other signals: a named address (anna.berg@) on a company domain is far more likely to be real than info@.

Frequently asked questions

Should I remove catch-all emails from my list?

Not automatically. Many are real business contacts. Send to them separately, in smaller batches, and remove the ones that bounce or never engage.

How common are catch-all domains?

They are mostly company domains; consumer webmail like Gmail or Outlook.com is not catch-all. In B2B lists they are a significant share.

Email validation API

Validate emails in your app

emailvalidation.io checks syntax, MX records and the mailbox over SMTP, flags disposable, role and free addresses and returns a quality score, in one request.

Read the docs

100 free validations every month. No credit card required.

GET https://api.emailvalidation.io/v1/info?email=support@emailvalidation.io

{
  "email": "support@emailvalidation.io",
  "domain": "emailvalidation.io",
  "format_valid": true,
  "mx_found": true,
  "smtp_check": true,
  "disposable": false,
  "role": true,
  "free": false,
  "score": 0.64,
  "state": "deliverable",
  "reason": "valid_mailbox"
}

Keep reading

Best email validation APIs in 2026Email verification APIs compared: emailvalidation.io, ZeroBounce, NeverBounce and Kickbox. Checks, free tiers and price per email at 5,000 to 100,000 verifications. Gmail and Yahoo sender requirementsWhat Gmail and Yahoo require from email senders: SPF or DKIM for everyone; SPF, DKIM, DMARC, one-click unsubscribe and a spam rate below 0.3% for bulk senders. Checklist with fixes. How to check if an email address existsHow email verification works: syntax, DNS and MX lookup, and the SMTP RCPT TO handshake that asks the mail server about a mailbox without sending a message. Plus its limits: catch-all, greylisting. How to reduce your email bounce rateWhat hard and soft bounces are, what bounce rate is acceptable, and seven ways to lower it: validation at sign-up, list cleaning, double opt-in, SPF, DKIM and DMARC. Validate email addresses in JavaScriptValidate emails in JavaScript: HTML5 input validation, a practical regex, typo hints, and checking that the mailbox exists with an API call from Node.js. Copy-paste code. Validate email addresses in PHPValidate emails in PHP with filter_var, check MX records with checkdnsrr, and verify the mailbox with an API call using cURL or Guzzle. Laravel validation rule included.

Start using our email validation software today!

Get 100 validations per month for free