Free Online
Email Verifier
Stop bounces. Protect your sender score. The most accurate bulk email verification platform.
CSV, XLS, XLSX supported
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High-Speed Email Verification
99% Accuracy
Stop guessing. Our multi-stage verification process ensures you only send to valid email addresses, protecting your sender reputation.
Zero Data Retention
Your privacy is our priority. We process your files in-memory and delete them immediately after verification. We never sell your data.
Save Money
Email marketing platforms charge by subscriber count. Why pay for 20% of your list that doesn't exist? Clean your list and lower your monthly bills.
Explore our guides & free tools:
Free Email Checker · Disposable Email Detector · How to Verify an Email Address · Bulk Email Cleaner · API Docs
Clean Your Email List - The Most Complete Solution
Our multi-layer verification engine goes far beyond basic syntax checks. We employ the most comprehensive email cleaning system in the market with advanced filtering that no competitor can match.
Multi-Layer Verification Process
Syntax Validation
First line of defense. We verify email format follows RFC 5322 standards, checking for proper structure, invalid characters, and malformed addresses.
DNS/MX Validation
We query DNS records to verify the domain exists and has valid mail exchange (MX) servers configured to receive emails.
SMTP Handshake
We perform real-time SMTP protocol verification by connecting to the mail server and validating the mailbox exists without sending actual emails.
Mailbox Verification
Real-time verification that the specific mailbox is active and can receive messages, detecting full mailboxes and disabled accounts.
Advanced Filtering Engine
Disposable Email Detection
Our database contains 71,910 disposable email domains. We catch temp mail services like Temp-Mail, Guerrilla Mail, 10MinuteMail, and thousands more.
Toxic Domain Blocking
We maintain a curated list of 312 toxic and abusive domains known for spam complaints, fraud, and malicious activity to protect your sender reputation.
Spam Word Filtering
Intelligent detection with 110 spam patterns including common spam keywords, suspicious character sequences, and bot-generated addresses.
Role-Based Detection
Identify role-based addresses (info@, support@, sales@) that typically have lower engagement and may violate GDPR consent requirements.
Smart Processing Features
Deliverability Protection
Hard Bounce Removal
Eliminate permanent delivery failures caused by non-existent mailboxes, invalid domains, and deleted accounts.
Soft Bounce ID
Detect temporary issues like full mailboxes, server problems, or message size limits that may resolve over time.
Catch-All Detection
Identify domains configured to accept all emails (catch-all), which have uncertain deliverability.
Greylisting Aware
Smart detection of servers using greylisting anti-spam techniques, ensuring accurate verification without false negatives.
How It Works
Upload List
Drag and drop your CSV or Excel file. We auto-detect the email column.
Kaiju Analysis
Our engine checks Syntax, DNS, MX Records, and SMTP response in real-time.
Download Results
Get a clean list of valid emails and a separate report of invalid ones.
The World's Most Powerful Free Email Verifier
Stop bouncing. Start connecting. Verify your email lists instantly with our enterprise-grade engine. No credit card required.
Frequently Asked Questions
Is it really free during beta?
Yes! During our beta period, we're offering unlimited email verifications completely free. No credit card required, no hidden fees. After beta, we'll offer 10,000 free verifications per month, then charge $0.47 per 1,000 emails - still the best price in the market.
How accurate is the verification?
We use a comprehensive multi-stage verification process including syntax validation, DNS/MX record verification, real-time SMTP handshakes, and mailbox verification. Combined with our advanced filtering for disposable domains (1M+ database), toxic domains, and spam patterns, we achieve 98%+ accuracy.
Do you store my email lists?
Absolutely not. We have a strict Zero Retention Policy. Your files are processed entirely in-memory and automatically deleted immediately after you download the results. We never log, store, or access your data. Your privacy is guaranteed.
What file formats do you support?
We support .CSV, .XLS, and .XLSX files. Our system automatically detects the email column regardless of how it's labeled. We also preserve multi-sheet Excel files - upload a workbook with multiple sheets and get all sheets back intact with only the email column cleaned.
What makes your cleaning more complete than competitors?
Most verifiers only check syntax and DNS. We go much further with: 1M+ disposable email domains database, toxic domain blocking, spam word filtering, role-based email detection, catch-all detection, greylisting awareness, and industry-first multi-sheet Excel preservation. No competitor offers this level of comprehensive filtering.
Why are some emails marked "Unknown"?
Some mail servers (especially Yahoo, AOL, and corporate domains) are configured to block verification attempts or return ambiguous responses for privacy/security reasons. Rather than guessing and risking false positives, we mark these as "Unknown" and let you decide how to handle them based on your risk tolerance.
What are disposable emails and why should I remove them?
Disposable emails (temp mail) are temporary addresses created through services like Temp-Mail, Guerrilla Mail, or 10MinuteMail. Users create them to avoid giving their real email. These addresses expire quickly and have zero engagement value. Our database tracks over 1 million disposable domains to protect your list quality.
How does multi-sheet Excel preservation work?
This is an industry-first feature. Upload an Excel workbook with multiple sheets (e.g., Contacts, Sales, Inventory) and our "Cleaned Database" download will preserve ALL sheets with their original names and data. We only clean invalid emails from the sheet containing the email column - all other sheets remain completely untouched.
What's the difference between hard bounce and soft bounce?
Hard bounces are permanent failures (non-existent mailbox, invalid domain, deleted account) - these MUST be removed immediately. Soft bounces are temporary issues (full mailbox, server down, message too large) that might resolve later. We clearly identify both types so you can make informed decisions.
Will this work with my email service provider (ESP)?
Yes! Our cleaned lists work with all major ESPs including Mailchimp, SendGrid, Constant Contact, ActiveCampaign, HubSpot, and any other platform. Simply export your list, clean it with Kaiju, then re-import the validated emails. Most ESPs charge by subscriber count, so cleaning your list also reduces your monthly costs.
How fast is the verification?
Our parallel processing engine verifies emails at high speed. For most lists, you'll see results within seconds to a few minutes depending on list size. Large lists (50k+ emails) may take longer due to SMTP rate limiting, but we're significantly faster than competitors thanks to our optimized infrastructure.
Can I use this for GDPR compliance?
Email verification helps with GDPR compliance by ensuring you're only emailing valid, reachable addresses. Our role-based email detection also helps identify addresses that may not meet consent requirements. However, verification alone doesn't guarantee GDPR compliance - you still need proper consent mechanisms and data processing agreements.