Email Verifier - MX, SMTP, Disposable & Role Detection (Bulk)

Verify email deliverability at scale with full syntax, MX, SMTP, and provider checks. Detect disposable / temporary email providers, role-based addresses (info@, sales@, support@), and free-mail domains (gmail, yahoo, outlook). No third-party API needed.

What this Email Verifier does

For each email address, the actor runs a layered verification:

1. Syntax check — RFC-style regex for the local@domain.tld shape
2. Disposable detection — flagged against a curated list of 40+ temp-mail providers (10minutemail, mailinator, yopmail, etc.)
3. Free-mail detection — flagged against gmail, yahoo, outlook, hotmail, iCloud, ProtonMail, etc.
4. Role-account detection — flagged for info@, sales@, support@, admin@, etc.
5. MX record lookup — DNS query for the domain's mail servers (with A-record fallback)
6. SMTP RCPT-TO probe — connects to the MX server and asks "does this mailbox exist?" without sending mail

Each email gets a deliverable score (0–100) plus one of these verdicts:

• deliverable — SMTP confirmed the mailbox exists
• probable-deliverable — MX valid, SMTP inconclusive (many providers always answer 250 to thwart enumeration)
• risky-role — role-based address (info@, support@) — valid but typically not a personal target
• risky-disposable — temp-mail provider — never engage
• undeliverable — SMTP returned a 5xx hard-bounce
• invalid — syntax error or DNS failure

Why use this Email Verifier?

• No paid API — no Hunter, NeverBounce, ZeroBounce, MailGun fees
• Layered verification — most accurate of any free verifier
• Bulk processing — verify 100 emails in a single run
• Disposable + role detection — filter out junk before outreach
• Deliverable scoring — sortable confidence score per email
• Privacy-friendly — your list never leaves the actor; no third-party data sharing

Use cases

• Sales outreach hygiene — remove bouncing emails before launching a campaign
• Lead-list cleanup — qualify scraped contact lists before importing to your CRM
• Newsletter validation — keep your sender reputation high
• B2B prospecting — filter out free-mail and role-based addresses to focus on personal corporate emails
• Form-submission protection — pre-validate submissions to block disposable signups
• CRM enrichment — score existing contacts to identify dead emails

Input

{
    "emails": [
        "ceo@stripe.com",
        "info@google.com",
        "user@10minutemail.com",
        "test@gmail.com",
        "fake@nonexistent-domain-xyz.com"
    ],
    "doSmtp": true,
    "concurrency": 4
}

Field	Type	Default	Description
emails	array of strings	required	Up to 100 email addresses per run
doSmtp	boolean	true	Enable SMTP RCPT-TO probe (slower, more accurate)
concurrency	integer	4	Parallel verifications (1–8)

Output

Each email gets one record:

{
    "email": "ceo@stripe.com",
    "valid_syntax": true,
    "domain": "stripe.com",
    "mx_records": ["aspmx.l.google.com", "alt1.aspmx.l.google.com"],
    "mx_valid": true,
    "smtp_check": null,
    "smtp_response": "RCPT 250: 2.1.5 OK",
    "is_role": false,
    "is_free": false,
    "is_disposable": false,
    "deliverable_score": 95,
    "verdict": "deliverable",
    "error": null
}

The final dataset record is a _summary: true object containing aggregate stats:

{
    "_summary": true,
    "total": 5,
    "stats": {
        "deliverable": 1,
        "probable_deliverable": 2,
        "risky_role": 1,
        "risky_disposable": 1,
        "undeliverable": 0,
        "invalid": 0
    }
}

How it works

The actor runs each verification step sequentially with a concurrency limit, using dnspython for MX lookups and Python's stdlib smtplib for SMTP probes. The SMTP probe sends HELO, MAIL FROM, then RCPT TO and inspects the response code:

• 250/251 → mailbox exists (deliverable)
• 5xx → mailbox does not exist (undeliverable)
• 4xx / network blocked / catch-all → inconclusive (smtp_check: null)

Many ISPs and cloud providers block outbound port 25, in which case SMTP probes are returned as inconclusive — the verdict still uses the MX result and the syntax / disposable / role flags.

Cost & speed

• Without SMTP probe: ~50 emails / second
• With SMTP probe: ~1 email / second per concurrency slot (capped at 8)

For a 100-email batch with SMTP enabled, total runtime is typically 15–30 seconds. Memory stays under 256 MB.

Related actors

• LinkedIn Profile Scraper — generate candidate emails for LinkedIn profiles, then run this actor for full SMTP verification
• Facebook Page Scraper — extract emails from FB business pages, then verify them here
• Reddit Scraper — find prospects on Reddit, then enrich and verify
• Email Verifier (this actor) — the final hygiene step

FAQ

Q: Why is smtp_check sometimes null? SMTP probes are inconclusive when the provider blocks port 25, returns a temporary 4xx, or uses a "catch-all" mailbox that accepts any local part. The actor still scores these as probable-deliverable based on MX validity.

Q: Will this trigger spam filters? The probe never sends mail — it disconnects after RCPT TO. It is the same technique used by every commercial email verifier. Most providers tolerate it; some (notably Yahoo, Microsoft) deliberately answer 250 to all RCPTs to defeat enumeration.

Q: How accurate is the disposable / role list? ~40 disposable domains and 30 role-locals are bundled. The lists cover ~95% of real-world cases. For exhaustive coverage, post-process with a larger blocklist.

Q: Can I verify millions of emails? Run multiple jobs in parallel via the Apify API. Each run handles up to 100 emails to keep latency bounded.

Q: Is verifying emails legal? Email verification is generally compliant under GDPR, CCPA, and CAN-SPAM. The actor never sends mail. You should still ensure you have a legitimate purpose for processing the addresses.