Bounce Email Checker

Find addresses that will bounce before you send. Protect your sender reputation and keep bounce rates below 2%.

Bounce Email Checker

Stop Bounces Before They Happen

Multi-layer SMTP verification identifies hard and soft bounce risks before your emails are sent. Protect your sender score and reach more inboxes.

Hard bounce detectionSender score protectionReal-time results
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BillionVerify bounce email checker result screen

Why Bounces Hurt Your Campaigns

A high bounce rate triggers ISP penalties that compound over time.

Lower Sender Score

ISPs track bounce rates and penalize senders who exceed safe thresholds, reducing future inbox placement.

Poor Deliverability

Once your reputation drops, more emails are filtered to spam β€” even to valid addresses.

Blacklist Risk

Persistent high bounce rates can get your domain or IP added to email blacklists.

Wasted Budget

Every bounced email costs a credit and contributes nothing. Clean lists before you pay per send.

How Bounce Detection Works

Four verification steps run on every address to assess bounce risk.

Syntax Check

Validates address format and detects typos before any network requests are made.

Domain Verification

Confirms the domain exists and resolves MX records to verify mail delivery is configured.

SMTP Test

Connects to the mail server to test whether the specific mailbox accepts incoming mail.

Bounce Risk Score

Combines all signals into a 0–100 risk score with a hard/soft/unknown bounce classification.

85%

Bounce Reduction

Average list improvement

<2%

Target Bounce Rate

After list cleaning

50K/hr

Processing Speed

Bulk verification rate

99.9%

Accuracy

SMTP-level verification

Frequently Asked Questions

1. What is an email bounce checker?

It identifies addresses that will bounce before you send. Hard bounces are permanent failures (mailbox doesn't exist). Soft bounces are temporary issues (full inbox). We detect both types so you can remove risky addresses from your list.

2. How does it work?

We check each email in multiple steps: syntax validation, domain and MX record checks, and a direct SMTP connection to test mailbox deliverability. The entire process runs at 99.9% accuracy in under 3 seconds per address.

3. How much can bounce rates drop?

Most users see an 85% reduction in bounces after cleaning. If your list bounces at 15%, expect to get below 2% after verification. Results are visible immediately.

4. Can I check addresses in bulk?

Yes. Upload a CSV file and we'll process thousands of addresses for bounce risk. The API also supports real-time single checks for forms and sign-ups.

5. How fast are the results?

Cached results return in under 200ms, and full SMTP verification completes in 1–3 seconds on average. Bulk processing handles 50,000 addresses per hour.

6. Is there a free tier?

Yes. Every account gets 100 free checks per day with no credit card required. You can test all features including API access before upgrading.

Bounce Email Checker

Stop Bounces Today

Check your email list for hard bounces before you send. Reduce bounce rates below 2% and protect your sender reputation.

100 free checks daily Β· 85% average bounce reduction Β· No credit card required

99.9%
Accuracy
Real-time
API Speed
$0.00014
Per Email
100/day
Free Forever