About this video

Addresses in this video are examples. File verification needs a paid account.

Video transcript

1. 00:00Why a yes isn't proof

   A catch-all domain accepts mail for any address, real or not. That changes what a yes is worth. Take three addresses on one domain. One belongs to a real person. One belonged to someone who left. One was never created. Ask the mail server about each, and it gives the same reply. That's the trouble with a plain yes. It might mean the mailbox is real. It might only mean this domain never says no.

2. 00:28How we detect it

   So we run a second test. We ask the same server about a made-up address that nobody would own. No email is sent. If the server refuses it, the domain isn't catch-all. If it accepts it, the domain is. If the test is blocked, or the server says try later, or the reply is unclear, we've got no proof either way. Now put the two answers together. Test refused and your address accepted gives valid. Test refused and your address refused gives invalid. Test accepted and your address accepted gives catch-all. If the test is accepted but your address isn't, the result is unknown. The reason shows which kind you have. Catch-all deliverable is the main one. Catch-all inferred means the evidence was cached or indirect. Some Microsoft 365 domains relay internally and take every recipient. Some security gateways do the same. And with a forwarding alias, the final recipient can't be known. All of this needs a live SMTP check. It runs by default. Through the API, check_smtp false skips it, and most addresses come back unknown. MCP tools default to false, so set it to true there if you want this test.

3. 01:41Should you send?

   So what does a catch-all result actually tell you? The domain will take the message. We can't confirm that a real mailbox sits behind that address. That makes it a judgment call, and the kind of mail decides it. High-value or transactional messages can usually go. For a cold bulk send, weigh it yourself. Either way, keep these addresses out of your valid list. In a file job, filter the results by status and export catch-all on its own. Now it's a decision you can see. Watch for one thing in that file. A role address on a catch-all domain shows as role, not catch-all, and its catch-all flag stays on. To find all of them, filter your CSV on ev_is_catchall. Don't count on a retry to settle it. Only unknown results get marked as retryable. A catch-all result uses one credit, the same as valid. Verify that address again on the same account within 24 hours, and there's no second charge. A forced refresh through the API is charged again. So give catch-all its own place. It isn't valid, and it isn't invalid. It's a yes from the domain, and the rest is your decision.

4. 02:53Get started free

   20 free credits every day you use your account, up to 600 a month. No credit card required. Start at billionverify.com.

Featured in this video

• Catch-All Email
• Why is an address marked catch-all instead of valid?