Verify any email
in milliseconds

Real-time email verification API. Check syntax, MX records, SMTP deliverability, and flag disposable or role-based addresses.

Try it free — 3 tests/hour · Sign up for 100 credits

Request
curl -X POST https://mailprobe.dev/api/v1/verify \
  -H "authorization: Bearer mp_live_..." \
  -H "content-type: application/json" \
  -d '{"emails":["alex@acme.co"]}'
Response ~1.2s
[{
  "email": "alex@acme.co",
  "result": "deliverable",
  "syntax": true,
  "mx_found": true,
  "smtp_check": true,
  "disposable": false,
  "role_based": false,
  "free_provider": false,
  "mx_records": ["mx.acme.co"]
}]

What you get

Syntax Validation

RFC-compliant email format check before hitting any server.

MX Record Lookup

Verify the domain has valid mail exchange servers configured.

SMTP Handshake

Connect to the mail server and check if the mailbox exists — without sending an email.

Disposable Detection

Flag temporary email addresses from known disposable providers.

Role-Based Detection

Identify generic addresses like admin@, info@, support@ that often bounce.

Catch-All Detection

Know when a server accepts all addresses regardless of existence.

How MailProbe works

Four steps from signup to a clean email list — no config, no infrastructure to run.

  1. 1

    Sign up in seconds

    Magic-link login, no password. You get 100 free credits to test the full API — enough to verify your own mailing list and see the accuracy first-hand.

  2. 2

    Grab your API key

    One key per account, visible on your dashboard. Rotate it any time. No OAuth dance, no IP whitelisting to configure — send it as a header or query parameter.

  3. 3

    Call the API

    Single POST /api/v1/verify per address, or batch up to 500 addresses per call from your backend. JSON response in seconds with status, reason, and response codes.

  4. 4

    Act on the result

    Block invalid signups, remove dead addresses before your next campaign, or flag catch-all domains as "risky" in your CRM. Every verification is a saved bounce and a protected sender reputation.

Who uses MailProbe

Built for teams that send email for a living — and can't afford a blocked domain.

SaaS & product teams

Verify emails at signup to kill fake accounts, trial abusers, and disposable inboxes before they pollute your metrics and waste onboarding emails.

Email marketers

Clean your list before every campaign. Cut bounce rate below 2% so Gmail, Outlook, and Yahoo keep delivering you to the inbox instead of the promotions tab — or worse.

Developers

Drop in real-time validation on contact forms, lead magnets, and newsletter signups. One HTTP call replaces regex patterns that miss 60% of invalid addresses.

Agencies & consultants

Clean imported client lists before you run a single send. Deliver measurable open-rate lifts in week one, justify the retainer from day one.

MailProbe vs alternatives

Email verification doesn't need to be complicated — or subscription-locked.

Feature MailProbe ZeroBounce NeverBounce DIY regex
Real-time API✓✓✓✗
SMTP handshake✓✓✓✗
Catch-all detection✓✓✓✗
Disposable & role-based✓✓✓Partial
Pay per use✓ creditsMonthly planMonthly plan—
Starts at (per check)$0.002~$0.007~$0.008Free
Free credits on signup1001001,000—
Credits expire1 year (reset on purchase)AnnuallyAnnually—
Dashboard + bulk API (up to 500/call)✓✓✓✗

Don't take our word for it — test with the 100 free credits on signup before committing a single dollar.

Why this matters

A stale email list isn't just noise — it silently degrades every campaign you send.

5–15%

invalid rate on purchased or old lists

Industry average for lists acquired via lead magnets, imported from CRMs, or left untouched for 12+ months. MailProbe catches them before your ESP does.

> 5%

bounce rate triggers throttling

Gmail, Outlook, and Yahoo penalize senders who bounce heavily. Once your reputation drops, recovery takes weeks — assuming the damage isn't permanent.

Seconds

per verification, not minutes

Fast enough to block invalid signups in real-time on form submissions, and batches of hundreds of addresses finish while you refill your coffee.

$20

buys 10,000 verifications

One cleaned campaign to an acquired list often pays for a full year of MailProbe credits. Credits stay valid for a full year and reset on every top-up — you only spend them when you check an address.

Simple pricing

Start free. Scale as you grow.

Free

$0
100 credits on signup
  • All verification features
  • Single & bulk API
  • Fresh verification every time
Get started

Starter

$5
1,000 credits
  • Everything in Free
  • $0.005 per verification
  • No monthly commitment
Buy credits

Pro

$20
10,000 credits
  • Everything in Free
  • $0.002 per verification
  • Best value
Buy credits

Built in the open, by devs who ship

MailProbe is new. Rather than fake testimonials, here's exactly what you're buying into.

Response time
~1.2s

Median verification latency, measured on live production traffic across typical consumer and B2B domains.

Transparency
Fullreason codes

Every response includes the exact check that returned the verdict — mailbox_exists, no_mx, disposable, catch_all, smtp_reject. No black box.

No lock-in
$0to start

100 credits on signup, no credit card. Credits never recur — you only spend what you explicitly top up, and they carry forward for a rolling 12 months.

Operated by Iris Digital — same team running ToolPulse, Postulus, and the rest of the network. The verification engine powers our internal email workflows before it's exposed here.

Frequently Asked Questions

How does MailProbe verify email addresses?
MailProbe performs real-time SMTP-level verification: syntax check, MX lookup, domain validation, catch-all detection, and deliverability check — all without sending an actual email.
Is the verification reliable?
Yes. We check syntax, DNS/MX records, and perform SMTP-level validation. Catch-all domains are flagged as "risky" rather than guessed, so you avoid false positives that would waste your send reputation.
Do you store the emails I verify?
We don't store the verified addresses beyond your own history for billing and UI purposes. No data is shared with third parties or used for other means.
What's the difference between Starter and Pro?
Starter = 1,000 credits for $5. Pro = 10,000 credits for $20 — cheaper per verification. Both include full API access and the web dashboard.
How does the API work?
Single POST /api/v1/verify with your API key as a Bearer token in the Authorization header and the emails in the JSON body. Returns a JSON array with result (deliverable, undeliverable, catch-all, unknown) and diagnostic flags (syntax, mx_found, smtp_check, disposable, role_based, free_provider, mx_records). Full documentation at /api-docs/.
Can I verify a bulk list of emails?
Yes. Send an array of up to 500 addresses in a single POST /api/v1/verify call from your backend or from a simple script. Credits are deducted per verification, not per call.
Do credits expire?
Credits stay valid for one year from your most recent purchase — and the clock resets every time you top up. No subscription, no recurring charge, just a rolling 12-month window that regenerates as long as you stay active.
Why should I verify emails before sending?
Invalid addresses cause bounces, and bounces above 5% get your domain throttled or flagged as spam by Gmail, Outlook, and Yahoo. Verifying upfront protects your sender reputation, improves deliverability across every future campaign, and stops you from paying your ESP to send to addresses that don't exist.
How accurate is email verification?
MailProbe achieves >98% accuracy on valid/invalid calls on typical lists. Catch-all domains (where the server accepts every address) are inherently unverifiable without actually sending — we flag those as "risky" instead of guessing, so you can decide whether to include them.
What's the difference between valid, invalid, and risky?
Valid = the mailbox exists and accepts mail. Invalid = syntax fails, domain has no MX records, or the mailbox explicitly rejects. Risky = technically accepted but uncertain (catch-all domains, role-based addresses like info@, or disposable providers). Most teams send to valid only and skip risky on cold campaigns.
Can I use MailProbe for real-time form validation?
Yes — verifications typically complete in a couple of seconds, fast enough to block invalid signups on form submission. Keep the API key server-side (never expose it in client-side JS), and proxy the request from your backend.
Is MailProbe GDPR-compliant?
We don't store the email addresses you verify beyond your own dashboard history (used for billing and UI). No verified data is shared, sold, or used for any other purpose. Full details on the privacy page.
Does verifying an email count as sending one?
No. MailProbe opens an SMTP connection with the recipient's mail server and asks "does this mailbox exist?" without ever transmitting a message. The recipient receives nothing — no email, no notification, no trace in their inbox.
What programming languages are supported?
Any language that can make an HTTP request — so all of them. The API is a plain POST /api/v1/verify that returns JSON. We show copy-paste examples for curl, Node.js, Python, PHP, and Go in the API docs.
What happens if I run out of credits mid-batch?
The API returns a 402 Payment Required response. Your batch stops cleanly — we don't charge for requests we couldn't fulfill. Top up from the dashboard and resume where you left off.

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