Real SMTP handshake checks
Every verification talks to the recipient's actual mail server. Syntax and MX checks alone miss the most expensive bounces: dead mailboxes on live domains.
Real SMTP verification · No email is ever sent
Email Bounce Checker
Test any email address before you send. We open a live SMTP handshake with the recipient's mail server and tell you whether the mailbox exists — so hard bounces never reach your campaign stats or your sender reputation.
- Real mailbox checks, not just syntax and MX lookups
- Catch-all resolution for Microsoft 365 and Google Workspace domains
- Bulk CSV cleaning and a simple REST API
Check an email now — free
5 free checks per day. No signup needed.
2%
bounce rate where providers start watching you
5%+
where reputation damage compounds fast
5–30s
for a full live SMTP mailbox check
100
free credits on signup — no card required
Why your bounce rate matters more than your open rate
Every hard bounce is a signal to Gmail, Outlook and every other mailbox provider that you don't know your own list. Providers track bounce rate per sending domain and IP, and they act on thresholds — cross them and all of your mail suffers, including the messages to perfectly good addresses.
The fix is simple and boring: never send to an address you haven't verified. Run new signups through the email bounce checker before they enter a sequence, and re-clean any list older than three months — addresses decay at roughly 2–3% per month as people change jobs and abandon mailboxes.
How the bounce check works
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1
Syntax & DNS
We validate the address format, then look up the domain's MX records to find the servers that actually accept its mail. No MX, no mailbox — instant fail.
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2
Live SMTP handshake
We connect to the real mail server and ask it, in its own protocol, whether the mailbox exists. The server answers; we disconnect before any message is sent.
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3
Catch-all resolution
If the domain accepts everything, most tools give up and say “risky”. We run provider-level identity checks on Microsoft 365 and Google Workspace domains to resolve whether the specific mailbox is real.
Everything you need to keep bounces near zero
Catch-all resolution
Provider-level identity checks resolve catch-all domains that other tools punt on as “risky” — with coverage for Microsoft 365 and Google Workspace, where most business catch-alls live.
Disposable & role detection
Throwaway domains and role accounts (info@, sales@, support@) are flagged automatically, along with a free-provider flag so you can segment business addresses from personal ones.
Bulk CSV cleaning
Upload a list of up to 50,000 addresses and download it back with a per-row status, reason and flags. Unknown results are refunded automatically on bulk jobs.
REST API
A simple key-authenticated API for single and bulk verification — verify at the point of signup so a bad address never enters your list in the first place.
Free to start
5 free checks a day on this page, and 100 free credits when you create an account. No card required, no trial countdown.
Simple credit pricing
1 credit = 1 verification. Credits never expire. Unknown results are never charged on single checks and refunded automatically on bulk jobs.
Start with 100 free credits — create an account, no card required.
Starter
1,000 credits
$10
Growth
5,000 credits
$40
Pro
10,000 credits
$70
Scale
50,000 credits
$300
Enterprise
100,000 credits
$500
Frequently asked questions
What is a good email bounce rate?
Keep it under 2%. Between 2% and 5%, mailbox providers start treating your traffic with suspicion and more of your mail lands in spam. Above 5% you are actively damaging your sender reputation, and sustained rates at that level can get a sending domain or IP blocklisted.
How do you verify an address without sending an email?
We open a real SMTP conversation with the recipient's mail server — the same handshake a sending server performs — and ask whether the mailbox exists, then disconnect before any message is transmitted. The address never receives anything and the owner never knows a check happened.
What does a “risky” result mean?
Risky means the address is technically accepting mail but carries elevated bounce or engagement risk — for example a catch-all domain we couldn't fully resolve, a disposable address, or a role account like info@. You can send to risky addresses, but segment them and watch the results.
Can it check catch-all domains?
Yes. Most checkers mark every address on a catch-all domain as risky and stop there. We run provider-level identity checks against Microsoft 365 and Google Workspace to resolve whether the specific mailbox actually exists behind the catch-all.
Is the email bounce checker free?
You get 5 free checks per day right on this page with no signup, and 100 free credits when you create an account — no card required. Paid plans start at $10 for 1,000 verifications.
Stop bounces before they happen
Clean your list today. 100 free credits, no card required.
Start verifying free