Stop fake signups & free-trial abuse.
Integrate email verification into your signup flow in minutes. Block 100,000+ disposable burner domains, prevent multi-account alias abuse, and protect your compute & sender reputation from $0.0002/check.
Built for developers
Block 100,000+ Burner Domains
Stop bots and temporary email providers from abusing your free trials or draining your AI API and GPU credits.
Real-Time Signup Verification
Verify emails synchronously at registration with our low-latency REST API and 99%+ verification precision.
Stop Gmail Alias Multi-Accounts
Canonicalize Gmail and ProtonMail dot/plus tricks ([email protected]) so one user cannot claim 50 free trials.
Protect Transactional Domains
Ensure welcome and password-reset emails never hard-bounce on Postmark, Resend, AWS SES, or SendGrid.
Integrate in minutes
Simple REST API works with any language. Verify emails before they enter your database.
- Real-time API response times
- Disposable email detection
- Typo suggestions
- Webhooks for async verification
// Verify user email (JSON or FormData supported)
const response = await fetch(
'https://api.mailveri.com/v1/verify-mail/',
{
method: 'POST',
headers: {
'Authorization': 'Bearer YOUR_API_KEY',
'Content-Type': 'application/json'
},
body: JSON.stringify({ email: userEmail })
}
);
const result = await response.json();
if (result.status === 'VALID') {
// Safe to send activation email
} else if (result.status === 'DISPOSABLE' || result.status === 'INVALID') {
// Block fake or disposable signup
}SaaS Registration Gate Policy — Recommended Handling by Status
Fail-open for enterprise B2B, hard-block for burners| API Status | What It Means at Signup | Recommended Gate Action | Credit Billed |
|---|---|---|---|
| VALID | Verified personal or corporate mailbox | Allow signup & send OTP / magic link | 1 credit |
| DISPOSABLE | 100,000+ temporary/burner provider | Hard block — ask for work/personal email | 1 credit |
| INVALID | Syntax error, dead MX, or non-existent user | Hard block — do not trigger welcome email | 1 credit |
| CATCH_ALL | Enterprise domain accepts all incoming mail | Allow through + require email link click | 1 credit |
| ROLE_ACCOUNT | Shared team inbox (admin@, devops@, team@) | Allow for B2B workspaces; flag in CRM | 1 credit |
| UNKNOWN-* | Transient mail server deferral or fast-skip | Fail open + verify via email confirmation | 0 creditsFree |
Protect Free Trials & AI Compute Quotas
Modern SaaS and AI applications face constant trial farming from temporary email generators (Mailinator, GuerrillaMail, YOPmail, 10MinuteMail). Blocking 100,000+ disposable domains at registration protects your GPU/compute budget and keeps product analytics accurate. See our Supabase, Clerk & Next.js Signup Gate Tutorial and AI Startups Industry Guide.
Safeguard Transactional Domain Reputation
When bots submit fake addresses into your signup form, your transactional provider (Postmark, SendGrid, AWS SES, Resend) immediately sends verification emails that hard bounce. Validating emails before triggering welcome messages keeps bounce rates strictly under 2%. Read our AWS SES, Postmark & Resend Bounce Prevention Guide, Gmail Plus & Dot-Trick Trial Abuse Guide, and SaaS Free-Trial Shield Playbook.
Frequently Asked Questions for SaaS Teams
How does MailVeri stop users from creating multiple free trials with Gmail aliases?
Abusers frequently register dozens of accounts using Gmail dot-insertion ([email protected]) or plus-addressing ([email protected]). Alongside blocking 100,000+ disposable burner domains, you can normalize ESP-specific alias syntax at registration so each real inbox can only claim one free trial.
How do we prevent signup bots from getting our AWS SES, Postmark, or Resend account suspended?
When bots submit thousands of fabricated addresses into an unprotected signup form, your app immediately fires verification or welcome emails that hard-bounce—quickly breaching AWS SES (5%) or Postmark/Resend (<2%) bounce thresholds. Calling MailVeri before sending the magic link or OTP email drops invalid and disposable addresses at the edge.
What should our SaaS signup flow do if the API returns UNKNOWN or CATCH_ALL?
For SaaS registration gates, we recommend failing open on CATCH_ALL and UNKNOWN-* (allow the user to proceed to email confirmation) while strictly blocking INVALID and DISPOSABLE. Because B2B corporate domains often operate as catch-all, allowing CATCH_ALL ensures legitimate enterprise buyers are never blocked while fake burner accounts are stopped at the edge.
Ready to clean up your signups?
Get your API key and start verifying in minutes. 1,000 free credits included.