Email Verifier

Verify any email address
before you hit send

Reduce bounces to <1%, protect your sender reputation, and reach every inbox with 98%+ accuracy — across any list size.

Verify 50 emails free Bulk Verifier →
4.8/5
G2
98%+
accuracy
<1%
bounce rate
GDPR
compliant
Verification Process

7-tier verification — the most thorough in the industry

Every email goes through seven independent checks before we mark it as verified. No shortcuts.

1
Format Check
Validates RFC 5322 syntax — catches typos and malformed addresses instantly.
2
Domain Check
Confirms the domain exists, is active, and accepts email traffic.
3
MX Record Check
Looks up the domain's mail exchange records to confirm email delivery is configured.
4
SMTP Handshake
Initiates a real connection to the mail server to confirm the mailbox exists without sending an email.
5
Catch-All Detection
Identifies domains that accept all emails regardless of whether the mailbox exists — and flags them accordingly.
6
Role Address Check
Flags generic role addresses (info@, support@, admin@) that are unlikely to reach a human decision-maker.
7
Disposable Address Check
Cross-references a database of 10,000+ temporary email providers and flags addresses that will expire.
Benefits

Why clean lists matter for your business

A high bounce rate doesn't just hurt deliverability — it can get your domain blacklisted permanently.

98%+ Accuracy

Our 7-tier pipeline achieves an industry-leading 98%+ accuracy rate. Every verified email has passed real mailbox existence checks — not just format validation.

<1% Bounce Rate

Customers who verify their lists with Leadsario before sending consistently report bounce rates below 1%, keeping their sender score healthy across all major ESPs.

Real-Time API

Integrate real-time verification into your signup forms, CRM, or outreach tool via our REST API. Verify emails in under 200ms before they enter your system.

GDPR Compliant

Leadsario does not store verified email addresses beyond your session. All verifications are processed in EU data centers under strict GDPR and CCPA compliance policies.

Use Cases

Who needs email verification?

Anyone who sends email at scale needs clean data. Here's who benefits most.

📧

Email Marketers

Protect your sender reputation, maintain high deliverability scores, and ensure every campaign lands in the inbox.

  • Clean your list before every major campaign send
  • Remove hard bounces and disposable addresses
  • Maintain inbox placement above 97%
  • Avoid blacklists from high bounce rates
🤝

Sales Teams

Stop wasting outreach sequences on invalid addresses. Verify before you sequence and only reach real people.

  • Verify prospect lists before loading into sequences
  • Eliminate wasted credits on undeliverable emails
  • Improve reply rates by targeting real inboxes
  • Keep CRM data clean automatically via API
⚙️

Developers (API)

Integrate real-time verification at the point of capture — signup forms, CRM entries, or data pipelines.

  • Validate emails at signup to block fake registrations
  • Enrich CRM data with verification status in real time
  • Process bulk verification via REST API or webhooks
  • Detailed JSON responses with all 7 check results

"We had a 7.3% bounce rate before using Leadsario. After running our entire database through the verifier, we're consistently below 0.7%. Our inbox placement went from 71% to 96% in one quarter."

SR
Sofia Reyes Email Marketing Lead at Intercom
Product Suite

Find, then verify, then send

Verification is one piece. Here's the full Leadsario workflow.

Email Finder

Find any professional's email — pre-verified at 98%+ accuracy.

Learn more →

Bulk Email Finder

Enrich entire prospect lists with emails and confidence scores.

Learn more →

Chrome Extension

Capture and instantly verify leads as you browse LinkedIn.

Learn more →

Deliverability Test

Ensure your sending domain is healthy before your next campaign.

Learn more →
FAQ

Email Verifier — common questions

What is the difference between "valid", "risky", and "invalid"?
Valid means the email passed all 7 checks — the mailbox exists and is deliverable. Risky means the email is on a catch-all domain or is a role address (e.g., info@) — it may be deliverable but is flagged for caution. Invalid means the email failed one or more checks and will definitely bounce. We recommend only sending to Valid results.
Does the SMTP handshake actually send an email?
No. The SMTP handshake is a "dry run" verification — we open a connection with the recipient's mail server and ask it to confirm the mailbox exists (RCPT TO command), but we disconnect before any message is sent. The recipient's inbox receives nothing, and no email is ever transmitted.
Can I verify emails in real time via API?
Yes. The Leadsario Verification API returns results in under 200ms for most addresses. It's designed for real-time integration into web forms, CRM workflows, and data pipelines. The API returns a full JSON object with the status of all 7 checks, a summary result (valid/risky/invalid), and a confidence score.
How do you handle catch-all domains?
Catch-all domains accept all incoming mail regardless of whether the specific mailbox exists, making standard SMTP verification impossible. Leadsario flags these addresses as "Risky — Catch-all" and applies pattern analysis and cross-database matching to estimate the likelihood the specific mailbox exists. We are transparent that these cannot be 100% guaranteed.
How many emails can I verify for free?
Free accounts can verify 50 email addresses per month. Invalid results do not consume credits. Paid plans start at 1,000 verifications/month and scale up to unlimited on Enterprise plans. Bulk verification of CSV lists is available on Starter plans and above.
Can I verify a full list of emails at once?
Yes. Upload a CSV with an email column and Leadsario will verify the entire list in parallel, returning a new CSV with the original data plus verification status, catch-all flag, role address flag, and confidence score for each email. Lists of 100,000 addresses are typically processed in under 30 minutes.

Stop sending to invalid emails

Verify your first 50 emails free. No credit card. Instant results.

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