Stop bad emails
before they reach your database.
Real-time signup validation. Block disposable emails, fix typos, score risk — before the form submits. 11 layers in one API call, under 50ms, on every plan.
The Engine
One API call. Eleven layers.
Every check, every plan. No premium tiers, no feature gates. Drop one API call into your signup form and you're done.
Syntax
RFC-compliant format
MX Records
DNS mail server lookup
SMTP
Mailbox exists + catch-all
Disposable
5,400+ throwaway domains
Typo
"gmial.com" → "gmail.com"
Role-based
Flags info@, admin@, noreply@
Free provider
Gmail vs business email
Gibberish
Catches keyboard-mash
Spam trap
Avoids known trap patterns
Domain age
Flags newly registered domains
Abuse patterns
Blocks toxic patterns
Sub-50ms · one call
All 11 layers run in parallel on every request.
Beyond Validation
Plus the tools you'd build yourself — already done.
Quality scoring, bulk CSV processing, email finding. All three included on every plan, including Free.
Quality Score
Every signal combined into a single 0–100 score. One number, one decision.
Reject
Review
Safe
Bulk Validation
Clean entire lists in one go. Upload, validate, download — that simple.
Email Finder
Enter a name and domain. We test common patterns and return the most likely address.
How it works
Three steps. That's it.
One endpoint. Any language. Copy, paste, ship.
Get your API key
Sign up free. Key issued instantly — no approval queue, no sales call, no credit card.
Send a request
POST to /api/v1/verify with the email address. One header, one field. That is it.
Get the verdict
Score, verdict, and all 11 checks in one JSON response. Typically under 50ms.
Developer experience
Built the way you'd build it yourself.
One endpoint. Idempotent. JSON in, JSON out. Official SDKs for the languages you actually ship in — plus clean cURL when you just want to try it.
One endpoint, one call
No multi-step verification, no webhooks to wire up. POST once, get everything back.
Honest error messages
4xx means you. 5xx means us. Bodies carry a machine-readable code plus a human hint.
SDKs for Node, Python, PHP, Go
Thin, typed, idiomatic. Same behaviour as cURL — no hidden retries, no magic.
Docs you can actually read
Every field documented with an example. Recipes for signup forms, bulk cleanup, and webhook hooks.
curl -X POST https:"color:#6B7280">//mailsentry.dev/api/v1/verify \ -H "X-API-Key: ms_live_..." \ -H "Content-Type: application/json" \ -d '{"email": "jane@acme.com"}'
Built for
Whoever owns the email pipeline.
Three ways teams drop MailSentry in — same API, same 11 layers, different problems solved.
Block bad signups at the form
One API call in your signup handler. Typos, disposables, and dead mailboxes stop at the gate — never hit your database.
Bad signups stop at the gate — before your CRM, your deliverability, or your billing get touched.
Block bad signups at the form
One API call in your signup handler. Typos, disposables, and dead mailboxes stop at the gate — never hit your database.
Bad signups stop at the gate — before your CRM, your deliverability, or your billing get touched.
Keep your sender score alive
Bounced emails destroy deliverability. Upload your list, separate safe from risky, ship to inboxes — not spam folders.
Typical projected bounce rate drops from 16% to under 2% after one clean pass.
Find real emails from public data
Give us a name and a domain. We test the common patterns, verify each one, and return the best hit with a confidence score.
Skip the guessing — one call returns the verified address plus the confidence that it's the right one.
Why MailSentry
The numbers other vendors won't print.
More layers, faster responses, honest pricing. And every feature shipped on every plan — including Free.
Syntax, MX, SMTP, typo, disposable, role-based, and 5 more — all returned in one JSON response.
Fast enough to run inline on a signup form without a loading spinner.
1,000/mo free plan + 5,000 bonus credits to test with a real list. No credit card.
10,000 checks a month. Every feature — bulk, finder, risk score, webhooks — included.
Pricing
Every feature, every plan. Including Free.
No per-check add-ons. No enterprise lock-ins. The Free plan runs all 11 layers — so you can ship, then pay only when you grow.
Every plan includes all 11 validation layers, bulk CSV, email finder, quality scoring, webhooks, and SDKs. No premium tiers. No feature gates.
If more than 3% of emails we mark “valid” bounce,
we credit your account.
Most providers mark catch-all emails as “valid” and leave you to deal with the bounces. We score them separately — analyzing the local part to tell you whether john.smith@ is likely a real person or xq7z@ is probably junk, so your score reflects actual deliverability, not just what the server accepted.
Applies to all paid plans. Emails must be sent within 30 days of validation.