FAQ

Quick answers to the questions we hear most often. If something isn't covered here, reach out to support — we're happy to help.

How is the trust score calculated?

Every email starts at a base score of 100. In Quick mode, we run it through 22 checks. In Deep mode, we run all 25 checks. Hard-fail checks (invalid syntax, no MX records, disposable domain, blocklist hit, known bounce, unroutable MX IP, SMTP rejection) instantly set the score to 0. Soft signals subtract points — for example, a role-based prefix (info@) is flagged informationally (0 points, no penalty), missing SPF or DMARC records cost 10 points each, DNSBL-listed domains cost 20 points, gibberish local parts cost 15 points, plus-addressing costs 5 points, and domains less than 30 days old cost 10 points. We also give bonuses: +5 for verified custom domains, +3 if a Gravatar profile exists (single verify only), and in Deep mode +5 for SMTP-confirmed mailboxes and +1 to +3 for name detection. Deep mode also checks for profanity (-10), domain web presence (+2/-5), and spam trap patterns (-10 to -30). The final score lands in one of four buckets: Safe (90+), Valid (60–89), Risky (20–59), or Invalid (below 20).

For the full check-by-check table, see the Email Verifier Overview.

What happens if I run out of credits mid-verification?

You won't. Credits are deducted upfront when you start a job, based on the number of unique emails in your list. If you don't have enough credits to cover the full list, you'll be asked to purchase more before the job can start.

Can I verify the same list twice?

Yes, but we'll let you know. When you upload or paste emails we've already seen in a recent job, you'll see a duplicate detection warning with the count of repeated addresses. You can choose to proceed anyway (useful if addresses may have changed) or skip the duplicates to save credits.

How long does bulk verification take?

It depends on list size and the responsiveness of each domain's DNS. As a rough guide:

You can close the browser and come back — the job runs in the background and results are stored for 15 days.

Are results guaranteed accurate?

We do our best, but email verification is inherently best-effort. Some mail servers don't respond to verification queries, DNS records can be temporarily unavailable, and catch-all domains accept everything (making it impossible to confirm a specific address). The trust score reflects our confidence level — treat it as a strong signal, not a guarantee.

Do purchased credits expire?

No. Credits you buy are yours forever. Use them whenever you need them.

Do monthly credits roll over?

No. Free monthly credits reset on your billing date. Any unused credits from the current cycle are lost. If you regularly need more than your plan includes, consider upgrading or purchasing a bulk credit pack.

Can I cancel a running job?

Yes. During Step 2 (Verify) of the wizard, click Cancel. Any emails that haven't been processed yet won't be charged — unprocessed credits are refunded to your balance immediately. You can also cancel from the history table below the wizard.

Can I download partial results?

Yes. If a job was cancelled or only partially completed, you can still download results for any emails that were processed in Step 3 (Results). The download filters (All, Safe only, Safe + Risky) work the same way as for completed jobs.

Is the API available on the Nano plan?

Yes. Every plan — including Nano — has access to the Email Verifier API with verify:read and verify:write scopes. The only limitation is your credit balance. See the Email Verifier API docs for endpoints and authentication.

What file formats are supported?

You can upload:

• CSV — we auto-detect the email column
• XLSX — same auto-detection as CSV
• TXT — we scan the entire file for email addresses

Or skip the file entirely and paste any text — we'll extract emails from whatever you give us.

What's the difference between Quick and Deep mode?

Quick mode (default) runs 22 checks using DNS lookups and pattern analysis. It costs 1 credit per email and is fast — suitable for most verification needs.

Deep mode runs all 25 checks, adding SMTP mailbox verification and spam trap heuristics. It costs 2 credits per email and takes longer because it connects to each domain's mail server.

When should I use Deep mode?

Use Deep mode when the quality of your list is uncertain or the stakes are high:

• Purchased or rented lists — these often contain dead addresses and spam traps
• Important campaigns — product launches, investor emails, anything where bounces would be damaging
• Leads from unknown sources — contest entries, scraped data, partner imports
• First-time verification of old lists — lists that have never been cleaned

For routine re-verification of your own opt-in lists, Quick mode is sufficient and more cost-effective.

Why can't Deep mode verify Gmail/Yahoo addresses?

Gmail, Yahoo, Outlook, and some other large providers use catch-all configurations — their mail servers accept all incoming connections at the SMTP level regardless of whether the specific mailbox exists. This means SMTP verification returns "inconclusive" for these domains. The trust score for these addresses relies on the other 24 checks. This is a fundamental limitation of SMTP verification that affects all email verification services, not just TrekMail.

How long does Deep verification take?

Deep mode is slower than Quick because it establishes SMTP connections to verify mailboxes. Rough estimates:

The job runs in the background — you can close the browser and come back when it's done.

What happens when I send to an invalid address?

Addresses that the Email Verifier has flagged as invalid are blocked at the server level. If you try to send to a suppressed address — whether from TrekMail Webmail, Thunderbird, Apple Mail, or any other email client — you'll receive a rejection message and the email won't be sent. This happens automatically and protects your sender reputation without requiring you to manually remove addresses from your contact list.