StopBouncingBad emails cost you more than you think.
Every bounce damages your sender reputation. Let it climb past 2% and your ESP flags your account — or suspends it without warning. StopBouncing verifies your entire list before you send, catching invalid, disposable, and catch-all addresses so your campaigns actually land.
100 free verifications · No credit card · Lists deleted within 48 h
Checking syntax · MX records · SMTP · disposable providers · catch-all
Works with every tool you already use
Export your verified CSV and import directly — no plugin, no API key, no configuration required
Using the API? Verify addresses in real time and pass the result directly to your CRM or form handler.
Why it matters
One bad send can end your email program
Email service providers enforce bounce thresholds without warning. The damage happens faster than you expect — and takes far longer to undo.
You send to an unverified list.
2% bounce rate. Your ESP flags your account.
Mailchimp, SendGrid, Klaviyo — all of them enforce bounce thresholds. Exceed 2% and deliverability drops immediately. Let it climb further and your account is suspended.
Your sender reputation takes the hit.
Future campaigns go to spam — even to your best subscribers.
Inbox providers score your sending domain continuously. A damaged reputation doesn't reset after one campaign. It compounds, silently burying your emails for months.
Rebuilding takes longer than breaking.
Months of warm-up. Lost revenue. Reputation recovery isn't guaranteed.
Getting unsuspended requires manual review. Reputation recovery requires months of low-volume warm-up sends. All of it avoidable with a one-time list clean before you sent.
The fix costs as little as €0.001 per address — less than any consequence above.
2–5%
Average bounce rate on unverified lists
Most senders don't know until the suspension notice arrives
6
Verification checks per email
Syntax · DNS · SMTP · Disposable · Catch-all · Role account
€0.001
Starting price per address
One-time list clean costs less than a single lost campaign
48 h
Maximum data retention
Your list is deleted permanently — not archived, not analysed
What cleaning your list actually does
15–25%
of any email list decays every year
People change jobs, abandon inboxes, sign up with throwaway addresses. Without verification, your list silently rots between campaigns.
2%
bounce rate is where ESPs start watching
Mailchimp, SendGrid, Klaviyo, and Brevo all enforce bounce thresholds. Exceed them and your account is flagged — or suspended without warning.
40%
higher open rates reported after list cleaning
Fewer bad addresses means more of your mail lands in inboxes, your reputation scores improve, and engagement metrics go up across the board.
What our users say
Email senders who verified before sending
We were sending to 74,000 contacts and our open rate had been sliding for six months straight. I assumed it was deliverability — it was the list. Ran it through StopBouncing, removed 11,400 dead addresses, and the next campaign came in at 38% open rate. Hadn't seen numbers like that in over a year.
Sarah Hendriks
Email Marketing Lead, Bloom Agency
Our Mailchimp account got flagged after a re-engagement campaign. We genuinely thought we had a clean list. Turned out 8% of it was dead weight — old job addresses, burner signups, catch-all domains. We verify every list now before it goes anywhere near a sending domain.
James Okafor
Co-founder, Volta CRM
We plugged the API into our sign-up form on a Friday afternoon. By Monday we'd already blocked over 200 disposable addresses from entering the database. Three weeks in and our transactional bounce rate had dropped by half. Setup was genuinely 20 minutes.
Mila Vosburgh
Head of Growth, Stacklead
How it works
Clean email list in three steps
No technical knowledge required. Works for 100 addresses or 10 million.
Upload your email list
Drop a .csv or .txt file — one address per row. We auto-detect the email column. Duplicates are removed before processing starts.
We run 6 verification checks
Syntax · DNS/MX records · SMTP mailbox · disposable email detection · catch-all domain · role account detection. Every address, every time.
Download your clean list
Get a CSV with a status column: valid, invalid, unknown, or disposable. Import directly into Mailchimp, Klaviyo, or any other tool.
What you get
Six checks. One clean list.
Every address goes through syntax validation, MX records, live SMTP, disposable detection, catch-all detection, and role account flagging — every time, automatically.
10,000 emails verified in under 3 minutes
Upload a CSV and walk away. Our engine processes your entire list in parallel — syntax, DNS, live SMTP — and hands you back a clean file ready to import.
Block fake signups before they touch your database
One API call at sign-up. Under 2 seconds. Invalid addresses and disposable emails are rejected at the door — not discovered after your first campaign.
The deepest check available — without sending a message
We simulate an SMTP handshake against the actual mail server to confirm the mailbox exists. No real email sent. No trace left. Maximum accuracy.
Catch-all and disposable addresses — never falsely removed
Mailinator, Guerrilla Mail, and thousands of burner providers are flagged automatically. Catch-all domains are marked unknown — so you never incorrectly drop a real contact.
API keys per environment — revoke in one click
Create separate keys for dev, staging, and production. Label them, monitor usage, revoke instantly. Hashed at rest. Full audit log in the dashboard.
No monthly fee. No expiry. Pay only when you verify.
From €0.001 per email. Buy credits when you need them — for a campaign, a quarterly clean, or a one-off scrub. Credits never expire, so nothing goes to waste.
Who it's for
Anyone who sends email has something to protect
Whether you're sending 500 emails or 500,000 — the cost of a dirty list always exceeds the cost of cleaning it first.
Marketing agencies
AgencyThe risk: A single client campaign with a dirty list can get their sending domain blacklisted — and that's your problem to fix, not theirs. Reputation damage takes months to reverse.
The approach: Verify every client list before it touches a sending domain. Offer it as a deliverability service. Automate with the API. Bill for the peace of mind.
Try the agency APISaaS & product teams
DeveloperThe risk: Every fake, disposable, or invalid signup that enters your database costs you — in transactional email bounces, inflated CRM counts, support noise, and skewed activation metrics.
The approach: Call the API at signup. Reject invalid and disposable addresses in real time, before they enter your system. One endpoint, under 2 seconds, no maintenance.
Read the API docsE-commerce stores
E-commerceThe risk: Abandoned cart flows, re-engagement campaigns, and post-purchase sequences all hit the same list. If that list has 10% bad addresses, 10% of your revenue potential goes to waste.
The approach: Run a list clean before any major campaign. Protect your Klaviyo or Mailchimp account from suspension. Keep your domain reputation where it needs to be to land in primary inboxes.
Start verifying freeNewsletter & media operators
NewsletterThe risk: You built your list one subscriber at a time. Bots, giveaways, and old addresses quietly inflate your count while your open rate slowly drops — and your sender score goes with it.
The approach: Verify before every major send. Remove what isn't real. Your open rate climbs, your deliverability improves, and your numbers actually mean something again.
Verify my newsletter listPricing
From €0.001 per email
Pay-as-you-go. The more you verify, the lower the cost per email. Drag the slider to estimate your price.
2,500
emails to verify
Estimated cost
€2.50
€0.00100 per email
Credits never expire · No subscription · EU-hosted
Included in every pack
- Credits never expire
- No monthly fee
- Bulk CSV + API access
- EU-hosted, GDPR-compliant
- Up to 63% cheaper at volume
Not sure how many you need?
Start with 100 free verifications
Create free accountNo credit card required
Need more than 1,000,000 emails? Contact us →
Get started today
Your next campaign deserves a clean list.
Verify your first 100 addresses free. See exactly what's in your list before it damages your sender reputation.
Need to verify more than 1,000,000 addresses? Contact us for volume pricing