Free Email Validation & Deliverability Scan
Validate syntax, DNS, MX, and risky inboxes in seconds without sending any email.
- Reach 99% accuracy on active domains with multi-step DNS checks and AI risk signals.
- Detect risky inboxes, spam traps, disposable and role accounts before they hit your CRM or ESP.
- PDPO / GDPR compliant with zero outbound traffic—we never email your contacts.
- Military-grade encryption and ISO 27001 data centers protect your insight data.
Accuracy
99.2%
Latency
< 150 ms
Checks
30+
Realtime diagnostics
- Run a validation to see the detailed timeline.
Recent lookups
- Your next lookup will appear here.
Why teams trust CloudOnHost
With our Hong Kong footprint, CloudOnHost delivers enterprise-grade validation backed by 30+ checks, AI detection, internationalization support, and military-grade security across APAC.
30+ layers of checks
Run syntax, DNS, role inbox, disposable, and policy signal checks in one pass.
Real-time scoring
Deliverability scores refresh in <150 ms so sales and marketing can act instantly.
Privacy-first
Invisible validation with zero probe emails or outbound traffic, fully PDPA / GDPR compliant.
AI-powered detection
Advanced neural models flag spam traps, honeypots, and elusive disposable providers with 99% accuracy.
Internationalization support
Accurately validate contacts that use non-Latin scripts with Unicode and Punycode support.
Military-grade security
TLS 1.3, one-way encryption, and ISO 27001 facilities keep every lookup protected.
Behind-the-scenes pipeline
Our pipeline executes dozens of checks within milliseconds. Each step maximizes accuracy while remaining fully private—we never send a probe to your contacts.
Format & syntax checks
Advanced syntax validation that follows RFC 5321/5322/1123, including quoted strings, comments, and domain literals.
Intelligent normalization
IDN + Unicode handling converts internationalized addresses via Punycode and UTF-8 to deliverable ASCII.
Domain, DNS & MX checks
Validate DNS records, spot invalid/parked domains, and confirm working MX records, including legacy setups.
Mailbox confirmation
Uses SMTP to confirm mailbox existence without sending mail, emulating popular MX providers for stealth validation.
28+ additional checks
Catch-all, temporary failure, role account, disposable email, spam trap removal, free mailbox signals, Yahoo verification, and more.
Advanced validation features
Comprehensive email validation powered by industry-leading technology.
Catch-All Detection
Identifies mail exchangers that accept all emails indiscriminately, including fake or non-existent addresses. This helps protect your sender reputation and open rates.
Temporary Unavailability
Detects mailboxes temporarily unavailable due to over quota or other issues. Premium services automatically retry to bypass graylisting.
Role Account Detection
Highlights generic role accounts (sales@, info@, support@) that may negatively impact deliverability and could lead to ISP blacklisting.
Disposable Email Check
Identifies temporary addresses from providers like Mailinator, YOPmail, and others. Our AI neural network detects even elusive providers like EmailOnDeck.
Spam Trap Removal
Exclusive AI technology detects and eliminates spam traps, honeypots, and individuals who frequently report spam from your lists.
Free Email Detection
Automatically flags addresses from free providers (Gmail, Yahoo, Hotmail, Outlook) so you can filter them based on your marketing strategy.
Built for growth teams
Embed the widget inside HubSpot, Salesforce, Zoho, or any landing page without touching code.
Sales & SDR teams
Stop wasting time on dead inboxes before outreach and improve reply rates.
Marketing ops
Embed validation on forms to keep CRMs pristine and protect sender reputation.
Product sign-ups
Block disposable addresses at onboarding to reduce fraud and churn.
Maximum security: military-grade encryption
Enterprise safeguards that protect every validation and dataset.
Advanced Data Encryption
Email addresses are protected with one-way military-grade encryption. Our system does not store verified addresses on disk, ensuring maximum security.
TLS v1.3 Protocol
Latest TLS v1.3 protocol ensures secure and encrypted communication. Multi-factor authentication and client-certificate TLS authentication available.
ISO 27001 Data Centers
Our eco-friendly data centers are ISO 27001 certified with video-monitored perimeter fencing, electronic access control, and 24/7 surveillance.
Automatic Data Deletion
All data is automatically deleted after validation according to your retention preferences (minimum 5 minutes, maximum 30 days), or you can delete manually anytime.
Frequently asked questions
Does the validator send an email?
No. Our checks stay server-side and never ping recipients. We verify mailbox existence using SMTP protocol without sending any messages to your contacts.
Can I validate bulk lists?
Yes. Connect the API or upload CSVs, Excel, or TSV files via our customer portal for batch cleaning jobs. Our system supports lists up to 40 million email addresses with smart duplicate removal.
What about accuracy?
We combine DNS + reputation data to reach 99%+ accuracy on active domains. Our AI-powered detection identifies spam traps, disposable emails, and role accounts with industry-leading precision.
What types of email addresses can you detect?
We detect catch-all domains, temporary unavailability, role accounts (sales@, info@), disposable emails, spam traps, free email providers, and verify complex Yahoo mailboxes. Our system also handles international addresses with non-Latin characters.
How secure is my email data?
Your data is protected with TLS v1.3 encryption, one-way military-grade encryption algorithms, and stored in ISO 27001 certified data centers. Email addresses are automatically deleted after validation according to your retention preferences (minimum 5 minutes).
Can I verify Yahoo email addresses?
Yes. Yahoo mailboxes are notoriously complex to verify, but our service includes specialized support for Yahoo's mail exchangers across all domain extensions (@yahoo.com, @yahoo.co.uk, @yahoo.de, @yahoo.es, @yahoo.it, etc.).
Need enterprise-scale list cleaning?
Connect the validator to signup forms, CRMs, or your marketing stack.
Talk to our engineers