Result statuses and reasons
Every result has one of four statuses, a reason that explains it, and a recommended action. Only unknown is free: results with any other status cost 1 credit when they come from a completed check.
The four statuses
| Status | What it means | Default action | Credit |
|---|---|---|---|
deliverable | The mailbox exists and accepted our check, so mail sent to it should arrive. | send (send) | 1 |
undeliverable | Mail sent to this address will not arrive, so it should come off your list. | remove (remove) | 1 |
risky | The address may accept mail, but sending to it can hurt your bounce rate or sender reputation. | send_with_caution (send with caution) | 1 |
unknown | We could not get a definite answer this time, so no credit is used and a later retry often succeeds. | retry_later (retry later) | Free |
Actions
The action is our recommendation for the address. It usually follows the status, but some reasons carry their own advice: a rarely used mailbox is deliverable with send_with_caution, and a disposable inbox is risky with remove.
| Action | What to do |
|---|---|
send | Keep the address and send to it as usual. |
send_with_caution | Send only if the address matters to you, and watch bounces and complaints for this segment. |
remove | Remove the address from your list or ask for another one. |
retry_later | Check the address again later; the answer often becomes definite on a second try. |
Every reason
Each reason links to its section on the status page, with an example response and a free test address.
| Reason | Status | What it means | Action |
|---|---|---|---|
accepted | deliverable | The mail server confirmed that this mailbox exists and accepts messages. | send |
alias | deliverable | The address is an alias that forwards to another mailbox, and mail sent to it is delivered. | send |
normalized | deliverable | We corrected a harmless formatting detail in the address, and the corrected address accepts mail. | send |
low_engagement | deliverable | The mailbox works, but it looks like a secondary address that its owner seldom reads. | send_with_caution |
high_engagement | deliverable | The mailbox works and shows signs of a person who reads mail regularly. | send |
trusted_catch_all | deliverable | The domain accepts mail for any address, but mail sent to it has a strong record of arriving. | send |
ai_agent | deliverable | The mailbox accepts mail and appears to be handled by an automated AI agent rather than a person. | send_with_caution |
no_mailbox | undeliverable | The domain receives mail, but this particular mailbox does not exist. | remove |
no_inbound_mail | undeliverable | The domain is set up to send mail only and turns away incoming messages. | remove |
invalid_syntax | undeliverable | The text is not a well-formed email address, so no mail server could ever accept it. | remove |
likely_typo | undeliverable | The domain looks like a misspelling of a common mail provider, so check the suggested correction. | remove |
no_dns | undeliverable | The domain has no DNS records that tell senders where to deliver mail. | remove |
mailbox_full | undeliverable | The mailbox exists but is over its storage limit and is turning away new mail. | remove |
unroutable | undeliverable | The domain points its mail to a server address that cannot be reached on the public internet. | remove |
catch_all | risky | The domain accepts mail for every address, so this specific mailbox cannot be confirmed. | send_with_caution |
role_account | risky | The address belongs to a team or function, such as info@ or sales@, rather than to one person. | send_with_caution |
role_catch_all | risky | A team or function address on a domain that accepts mail for every address. | send_with_caution |
disposable | risky | The address comes from a throwaway mail service whose inboxes are usually abandoned quickly. | remove |
toxic | risky | The address is associated with spam, abuse or automated sign-ups. | remove |
forwarding_domain | risky | The domain only relays mail to mailboxes elsewhere, which hides whether the final mailbox exists. | send_with_caution |
suppressed | risky | The address appears on widely shared do-not-contact lists, often after earlier bounces or complaints. | remove |
possible_trap | risky | The address follows patterns that traps often use, so mailing it can damage your sender reputation. | remove |
spamtrap | risky | The address is believed to exist only to catch senders who mail lists without consent. | remove |
complainer | risky | The person behind this address often reports legitimate mail as spam. | remove |
server_unavailable | unknown | The mail server refused or dropped our connection, so the mailbox could not be checked. | retry_later |
temporary_error | unknown | The mail server reported a temporary problem while we were checking the address. | retry_later |
greylisted | unknown | The mail server asked us to come back later, which is a common anti-spam delay. | retry_later |
anti_spam_block | unknown | An anti-spam system in front of the mail server stopped our check before it could finish. | retry_later |
timeout | unknown | The check did not finish within the time limit, so we stopped waiting and charged nothing. | retry_later |
internal_error | unknown | Something went wrong on our side while checking this address, so no credit is used. | retry_later |
What a result can and cannot tell you
deliverableis a snapshot. The mailbox accepted our check at that moment. It can still bounce later if the mailbox is closed, fills up, or the receiving server starts refusing your mail.- Catch-all domains cannot be confirmed. They accept every address during a check, so the specific mailbox may or may not exist. These results are
riskywith the reasoncatch_all, unless the domain has a strong record of delivering mail (deliverable, reasontrusted_catch_all). unknownis not a verdict. It means we could not get a definite answer this time, so it costs nothing. Checking again later often gives a definite result.
Related
- Test addresses that return every reason for free.
- Catch-all emails explained.
- Credits and billing: what is free.