How do I check whether an email address is valid?

Open Prospecting > Email verification in the sidebar (/verify). Type an address and press Verify, or switch to Bulk upload to check a list. Warmerly tells you whether the address is Safe to send, Send with caution, Do not send, or Unknown, with a confidence score and a plain reason. A standard check does not send a message to the address.

For the developer version, see the Verify API.

Check one address

1. Open Email verification and stay on the Single check tab.
2. Type the address (for example name@company.com) and press Verify or Enter.
3. Read the banner at the top of the result: the recommendation, a one-line reason, and the confidence score.
4. Press Show details to see the individual checks.

If Warmerly remembers a recent result for the address, it shows that instantly and free, and a Re-check button appears to run a fresh check.

What the recommendations mean

Behind those sit the underlying statuses shown in tables and exports: valid, invalid, risky, catch-all and unknown.

• Valid with a high confidence becomes Safe to send. A valid address that is a shared inbox (info@, support@ and similar) becomes Send with caution, because it will not reach a specific person.
• Catch-all means the company's mail server accepts mail for any address at the domain, so one exact address cannot be confirmed. Google Workspace and Microsoft 365 behave this way for outside checks, so many business addresses land here. It is a limit of what can be known from outside, not a fault with your list.
• Risky means the domain has a mail server but the mailbox could not be confirmed.
• Unknown means the check was blocked or unreachable. Ambiguity is never turned into Invalid: an address is only marked Invalid when there is hard evidence (bad format, no mail server, a disposable domain, or the server explicitly saying the mailbox does not exist).

The checks under Show details

Format, Mail server reachable, Mailbox accepts, Catch-all, Disposable, Shared inbox, Free provider (Gmail, Yahoo and similar), Can receive email (does the domain have mail records), and the mail Provider. If the domain looks like a typo of a well-known one, a "Did you mean" suggestion appears that you can click.

Confirm an uncertain address with a test send

When a single check comes back Catch-all, Risky or Unknown, a Confirm with a test send button appears. It sends one short automated message from one of your connected mailboxes to that address and watches your inbox for a bounce for a few minutes.

• A bounce means the mailbox does not exist, and the result becomes Do not send.
• No bounce means the address accepted the mail, and the result becomes confirmed valid.
• The recipient does receive a short message titled "Deliverability check", so use it only on addresses you would be comfortable mailing.
• It needs a connected mailbox that Warmerly can read the inbox of. Without one you will see "No usable warmup account found. Connect an account (with inbox access) to run a test send."
• It is a real email from your mailbox, so it counts like any other send for that mailbox's reputation. Use it to settle a handful of ambiguous addresses, not a whole list.
• It is not billed as a separate verification.
• It cannot settle a true catch-all domain: such a server accepts the message and never bounces, so "no bounce" does not prove the mailbox exists.

Check a whole list

1. Switch to the Bulk upload tab.
2. Paste addresses (one per line, or separated by commas), or press Upload CSV / TXT.
3. The page shows how many addresses are ready. Press Start verification. For very large lists (over 2,000) you are asked to confirm, because it uses part of your allowance and cannot be stopped once started.
4. Results fill in as they are checked. A batch can hold up to 50,000 addresses, and duplicates in the paste are removed.

Uncertain answers (for example a server that asks Warmerly to try again later) are retried automatically a few times before being reported. For some uncertain addresses in a bulk list, Warmerly may also settle the answer with a real test message from a mailbox Warmerly operates itself. It is never sent from one of your mailboxes, and only within strict limits.

Each batch is saved under Recent batches and in the Data library, so you can come back to it.

From the results you can:

• Export as CSV or Excel (columns: Email, Recommendation, Status, Confidence, Reason).
• Add to campaign. Only Safe to send addresses are included by default. Untick the option to also add Send with caution ones. Do not send and Unknown addresses are never added.

What it costs

Each address that gets a fresh check uses one email verification from your monthly allowance, which resets on the 1st. Results Warmerly already knows are free: a repeat check of the same address within its memory window, and any observed fact, costs nothing. Uncertain results are remembered for a shorter time than certain ones, so they are re-checked sooner. A check that is retried is only charged once it has a final answer.

Before a bulk batch starts, Warmerly checks your remaining allowance covers the whole batch, counting addresses from earlier batches still in the queue. If not, the batch is refused and nothing is queued. Check Settings > Usage & limits (where you can also buy more with credits), see Lead credits, lookups and allowances, and Plans & limits for the size of the allowance on your plan.

The quick checks that run when you import leads or add leads to a campaign (format, disposable domains, mail server present) are free and do not use this allowance. See How do I import leads from a CSV?.

What it cannot do

• It cannot guarantee delivery. A valid mailbox can still bounce later, be full, or be deactivated tomorrow. Results are a snapshot.
• It cannot see inside catch-all domains or resolve every Microsoft 365 or Google Workspace address. These show as Send with caution or Unknown, not as a false Valid.
• It cannot tell you the person is interested, only whether the mailbox exists.
• Checks are paced gently per mail server to avoid looking like address harvesting, so a big list of addresses at a single company is slower than a mixed list.

Common problems

• Lots of "Send with caution". Usually catch-all or shared inboxes. They are fine to send to in moderation, and a test send can settle single addresses.
• Unknown on an address that looks fine. The receiving server blocked or timed out. Press Re-check later.
• The result changed after Re-check. Re-check runs a fresh test, and mail servers change. If Warmerly has direct evidence about a mailbox (a bounce or a reply), that evidence is kept and is not overwritten by a re-check.
• A message about your verification allowance. It is used up. Buy more with credits, upgrade, or wait for the 1st.

Related

• How do I find someone's email address?
• How do I find leads with Find leads?
• Verify API