Use case · SimpleVerifier Team
Email verification for cold email
Verify a cold list right before it goes into your sequencer. Send only to addresses the recipient's mail server confirmed as valid, move catch-all (risky) addresses into a separate low-volume campaign, and remove every invalid one. Cold prospects never opted in, so mailbox providers judge your domain on bounces from the very first touch.
Cold email is where verification matters most and forgives least. A newsletter subscriber who bounces once signed up at some point. A cold prospect never did, so there is no engagement history to offset a bad send, and the sending domain is usually a fresh secondary domain with little reputation to spend.
The goal is not a perfect list. It is a main campaign where every address was confirmed by the receiving server, and a clear rule for the addresses that could not be confirmed either way.
What goes wrong on a cold list
Sequencers pause on their own maths, not the provider's
Instantly auto-pauses a campaign at a 5% bounce rate by default, checked once 200 emails have gone out. Smartlead divides bounces by every lead in the campaign, so its figure reads lower than what the mailbox providers saw. lemlist alerts at 10%. The sources and a worked example are in bounce limits by platform. These lines stop a campaign after the damage, they do not protect the domain.
Catch-all domains hide dead mailboxes
A catch-all server says yes to any recipient during the mailbox check, so the real address cannot be confirmed or ruled out. In our Email List Health Report 2026, 27.5% of 54,463 domains accepted mail for a made-up address: 46.7% of Google Workspace domains, 23.2% of Microsoft 365 domains and 60.3% of domains behind a security gateway. Company prospects sit on exactly those platforms.
New sending domains have nothing in reserve
Most cold senders warm up secondary domains for weeks before a campaign. A bounce spike in the first sends after warm-up undoes that work, and a pause from Gmail or Workspace applies to the inbox, not the campaign. Setup is covered in cold email domain setup and the warm-up schedule.
Role addresses reach a team, not a person
info@, sales@ and hello@ usually exist, but a personalised first line sent to a shared inbox reads as spam to everyone who sees it. These come back as risky with the reason Role-based address, so you can pull them out in one filter. More in role-based email addresses.
From lead source to first send
Pull the list as late as you can
Export from Apollo, Sales Navigator, Clay or your own research in the days before the campaign starts, not weeks before. People change jobs, and a verification result is a snapshot of the day it ran.
Upload the export as it is
No reformatting. The email column is found automatically, and every other column, including first lines and custom variables, comes back in the output files. Step-by-step guides: Apollo, Clay, Sales Navigator.
Give catch-all addresses their own campaign
Put risky catch-all rows in a separate campaign sent from one or two well-warmed inboxes at low daily volume. Watch the first hundred sends. If hard bounces appear, stop and drop the rest of that segment. The trade-offs are in should you send to catch-all emails.
Re-verify anything that sat in a sequencer
Leads that waited two months for a follow-up step are not the leads you verified. Results are cached for 14 days, after which a re-run checks the mailbox again, and on Pro re-running does not add to the bill.
Which results go into a cold campaign
| Result | What to do | Why |
|---|---|---|
| valid | Send | The recipient's server confirmed the mailbox. This is your main campaign. |
| risky · Accepts all addresses | Separate low-volume campaign | Catch-all domain. The mailbox may be real or dead and nothing over SMTP can tell. Never mix these into the main send. |
| risky · Role-based address | Usually remove | Shared inbox. Keep only when the pitch is genuinely for the team, such as a partnership note to partners@. |
| risky · Server would not confirm | Hold, re-verify tomorrow | Often greylisting or a temporary refusal. A second run a day later frequently resolves it. |
| invalid | Remove | Mailbox not found, no mail server, broken syntax or a disposable domain. Each one would be a hard bounce. |
Common questions
- What bounce rate is safe for cold email?
- No mailbox provider publishes a bounce limit for cold email. Among sending platforms, the lowest published line is Brevo's 2% hard bounce rate, and Instantly pauses campaigns at 5% by default. Staying under 2%, measured as hard bounces divided by emails actually sent, keeps you under every published line.
- Should I send cold email to catch-all addresses?
- Only separately and slowly. A catch-all domain accepts every recipient during the check, so the result is risky rather than valid. Send those rows as their own low-volume campaign from well-warmed inboxes and stop if hard bounces appear.
- Does verifying a list stop cold emails going to spam?
- No. Verification removes addresses that would bounce. Inbox placement also depends on SPF, DKIM and DMARC, volume per inbox, content and how many recipients mark you as spam.
- How often should I re-verify a cold email list?
- Before every campaign and before any sequence step sent to leads that have been waiting for weeks. Confirmed results are reused for 14 days; after that the mailbox is checked again.
- How much does verification cost for cold email volume?
- Pro is $29.99 a month with no cap on verifications and CSV uploads up to 100,000 rows, so re-verifying lists before each campaign does not change the price.
Verify your next cold list
Pro is $29.99 a month with no cap on verifications: CSV uploads, the API, the Google Sheets add-on and the email finder are all included. Cancel any time.
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