MailSift

Email verification,
built for engineers.

One API call returns disposable status, domain reputation and a trust score, in under 100 ms on average.

Start free API Docs
No credit card500 free checksGDPR ready
Try it livePOST /v1/verify

Enter any email to check syntax, MX records, SPF, DMARC, disposable and role-based signals in real time. Protected by MailSift.

15+
Checks per request
<100ms
Average response time
500k+
Disposable domains tracked
500
Free checks to start
What we catch

Every fraud signal in one call.

Disposable inboxes, relays, typos, role addresses and more — scored together so you can act on a single number.

Reject

Mail to these addresses will not arrive.

Syntax & RFC

Strict parser rejects malformed addresses long before any network call.

"syntax": false

Dead domains

Domains that cannot receive mail at all, caught before they hit your sender reputation.

"mx": false

Missing mailboxes

Deep Verification asks the receiving mail server whether the mailbox itself exists.

"smtp": { "status": "undeliverable" }

Disposable inboxes

Throwaway addresses from 500k+ tracked providers, plus heuristics for new ones.

"disposable": true

Review

Deliverable, but probably not the person you think.

Relay forwarders

SimpleLogin, AnonAddy, Apple Hide My Email, Firefox Relay and friends.

"relay": true

Role addresses

Generic inboxes like info@, admin@, support@ that lower engagement and CTR.

"role": true

Catch-all domains

Domains that accept any local part, masking whether the mailbox is real.

"catch_all": true

Domain typos

Suggests fixes for gmial.com, hotnail.com and other lookalikes in real time.

"did_you_mean": "gmail.com"

Context

Signals to route and segment on.

Domain age

Brand-new domains are flagged. Established providers get an integrity boost.

"domain_age_days": 4823

SPF & DMARC

Live DNS lookup validates the domain has proper email authentication set up.

"spf": true, "dmarc": true

MX provider

Identifies Google, Microsoft, Proton and dozens more — useful for routing logic.

"mx_provider": "Google"

Free providers

Tags gmail.com, outlook.com and similar so you can route signups by audience.

"free": true

Trust score 0–100

Every signal rolls up into one score. Route by risk, not handwritten if-trees.

"score": 95

Mailbox verification

Deep Verification

Every check above reads DNS and reputation. This one opens an SMTP conversation with the server that owns the mailbox and asks whether the address exists. Providers that refuse to answer are reported as unknown rather than guessed at, so a confirmed result means confirmed.

1 credit standard, up to 5 for deep →
"smtp": { "status": "deliverable",
        "catch_all": false }
Drop-in API

One request. Complete intelligence.

A single GET request returns disposable status, domain reputation, risk score and 15+ checks. Try it live — runs against the production API.

bash
$curl "https://mailsift.dev/api/v1/verify?email=" -H "X-API-Key: msk_..."
Loading verification…
Complete the captcha to run
Example response · [email protected]
29 lines
{
  "email": "[email protected]",
  "status": "valid",
  "score": 92,
  "mode": "fast",
  "credits_used": 1,
  "checks": {
    "syntax": true,
    "free": true,
    "disposable": false,
    "mx": true,
    "relay": false,
    "spf": true,
    "dmarc": true,
    "role": false,
    "catch_all": false
  },
  "domain": "gmail.com",
  "mx_records": [
    "gmail-smtp-in.l.google.com",
    "alt1.gmail-smtp-in.l.google.com"
  ],
  "normalized_email": "[email protected]",
  "mx_provider": "Google",
  "is_catch_all": false,
  "domain_age_days": 11188,
  "response_time_ms": 46,
  "checked_at": "2026-04-01T17:32:18Z"
}
Edit the address above, or try:

Five layers, one verdict.

Raw email in. Routing decision out. Each layer runs in parallel and contributes to the final score.

  1. 01Syntax & format
  2. 02DNS & MX lookup
  3. 03Domain intelligence
  4. 04Mailbox verification
  5. 05Trust scoring
Simple pricing

Pay once. Use anytime.

No subscriptions. No expiry. Credits never burn.

Free

$0/ at signup
500 verification credits
Start free
  • 1 req/sec rate limit
  • No credit card

Starter

$10/ one-time
25,000 verification credits
Buy credits
  • 10 req/sec rate limit
  • $0.40 per 1,000 checks
Most popular

Growth

$35/ one-time
100,000 verification credits
Buy credits
  • 25 req/sec rate limit
  • $0.35 per 1,000 checks

Pro

$99/ one-time
350,000 verification credits
Buy credits
  • 50 req/sec rate limit
  • $0.28 per 1,000 checks
Every account includes
  • All 15+ checks on every request
  • Single, bulk CSV and API verification
  • Deep Verification, charged per result
  • Webhook notifications and CSV export
  • Credits never expire
Need more? See full pricing.

Start verifying in 60 seconds.

Grab an API key, drop in three lines of code, and stop fake signups before they hit your database. Free tier never expires.

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MailSift is operated by NORTHPIN INC. Read the data processing agreement and the privacy policy, or check the service status.