Live SMTP Verification Engine

Email Verification
that kills bounces.
At scale.

Real-time SMTP handshake verification that flags bad emails before they torch your sender reputation. Buy credits, upload your list, get results.

Start verifying free See how it works
Free 100 credits · No credit card · No subscription
97% accuracy
Silent SMTP handshake
No emails sent to verify
Credits never expire
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stellarverifier.com
Stellar Verifier
Verify Bulk Upload History API & Integrations
9,247 credits
marketing_list_march_2026.csv
12,450 emails processed · Completed 3 minutes ago
✓ Complete
✓ Safe
9,711 78%
⚠ Risky
1,494 12%
✕ Invalid
1,245 10%
9,711 safe emails ready — 2,739 filtered out
cold_outreach_feb.csv8,200 emails✓ Complete
newsletter_subscribers.xlsx34,780 emails✓ Complete
97%
Accuracy Rate
8
Verification Layers
$0
Monthly Fees
0
Emails Sent to Verify

Built to protect your
sender reputation

Every credit goes toward keeping bad emails out of your sends — before they cost you far more in deliverability.

Most Popular

Bulk list verification,
at any scale

Upload CSV, XLSX, or TXT — even with extra columns. Credits deduct only for emails processed. Results back in your original format, clean and ready to send.
CSV XLSX TXT Any column order
Zero Footprint

Verify without
sending a single email

We knock on the mail server door and walk away. No test emails, no bounces logged, no footprint on their end. Your domain reputation stays spotless.
Live SMTP handshake No test sends
Deep Scan

8 checks.
One credit. One verdict.

Format, DNS, MX records, SMTP handshake, disposable inbox detection, role-based flagging, catch-all handling, and more — all in one pass.
Format check
Disposable inbox
DNS / MX lookup
Role-based address
SMTP handshake
Catch-all detection
Developer Ready

Drop it into any
stack with one API call

One endpoint, one key, one credit per call. Integrate into your signup flow, CRM, or outreach tool in minutes.
POST /v1/verify
{
  "email": "john@company.com"
}

→ { "status": "safe", "score": 97 }

Buy credits. Verify. Done.

No subscriptions, no dashboards to configure, no waiting on support.

Buy Credits & Upload

Purchase a credit pack — no subscription needed. Drop in a CSV, XLSX, or TXT and pick your email column. That's it.

Credits Deduct Per Email

One credit per verification. Our engine runs 8 checks using live SMTP — no emails sent, no risk to your sender reputation.

Download Clean Results

Get your original spreadsheet back with a status column: Safe, Risky, Invalid, or Unknown. Export and deploy immediately.
results_verified.csv Complete 4 of 4 verified
john.smith@company.com✓ Safe
noreply@domain.io⚠ Risky
fake.address@nowhere.xyz✕ Invalid
contact@enterprise.com✓ Safe
Integrations

Plug into your stack

Connect via REST API, Zapier, or Make. Your clean list flows straight into the tools you already use.

Zapier
n8n
Slack
HubSpot Coming Soon
Salesforce Coming Soon
Apollo Coming Soon
Clay Coming Soon
Instantly Coming Soon
Smartlead Coming Soon
Reachinbox Coming Soon
Lemlist Coming Soon
Pipedrive Coming Soon
Close Coming Soon
Klaviyo Coming Soon
Mailchimp Coming Soon
ActiveCampaign Coming Soon

All brand names and logos are property of their respective owners.

Pay per verification.
Nothing else.

One credit = one verified email. No monthly fees, no expiry, no overages.

Free

$0
100 credits · every month
  • 100 email verifications/mo
  • Bulk CSV upload
  • Full history & export
  • API access
Start Free
Most Popular

Growth

$29
10,000 credits · one-time
  • 10,000 credits (1 per email)
  • Bulk CSV upload
  • Full history & export
  • API access
  • Priority processing
Get Started

Pro

$79
50,000 credits · one-time
  • 50,000 email verifications
  • Bulk CSV upload
  • Full history & export
  • API access
  • Priority processing
  • Dedicated support
Get Started
How many emails to verify?
10,000 emails
You pay
$29
$0.0029 per email
Credits never expire
No subscription · cancel anytime
100 free credits on signup
No credit card required

Frequently asked questions

How does verification work without sending emails?
We perform a live SMTP handshake — we knock on the mail server's door, check if the mailbox exists, then walk away before any email is sent. No test message lands in the inbox, and no bounce is logged against your domain.
Do credits expire?
Never. Credits you purchase are yours indefinitely. The only exception is the free 100 monthly credits on the Free plan — those reset each month.
What file formats do you support?
CSV, XLSX (Excel), and TXT files. Your original file structure is preserved — we add a single Status column and return it in the same format you uploaded.
What do Safe, Risky, and Invalid mean?
Safe means the SMTP server confirmed the mailbox exists and is accepting mail. Risky covers catch-all domains, role-based addresses, and disposable inboxes. Invalid means the address doesn't exist or was rejected outright.
Can I use the API for real-time verification?
Yes. One POST request, one credit, one verdict. Drop it into your signup form, CRM, or outreach tool. Returns Safe / Risky / Invalid in under 3 seconds on average.
How accurate is it?
97% on verifiable addresses. The remaining edge cases are catch-all servers that accept all mail regardless of whether the mailbox exists — these are flagged Risky so you can make an informed decision.
Start scaling your
outreach today
Buy credits once. Verify on your schedule. No subscription. No risk.
Get your first credits →