How to Clean an Email List Before You Hit Send

Every cold email to a dead address costs you twice. You pay to send it, and you pay again in sender reputation — bounces pile up, mailbox providers take note, and eventually your good emails start landing in spam. Most senders don't notice until their open rates quietly fall off a cliff.

The fix is unglamorous but decisive: verify the list before you send. Not just "does this look like an email" — actually ask the mail server whether the inbox exists. That's what our Fast Email Validator & Verifier does, and it can also find the addresses you're missing. Here's how to use both.

Past the surface: three layers of checking

Plenty of "validators" stop at a regex. They'll happily wave through a perfectly-formatted address to a mailbox that was deleted two years ago. This one checks in layers:

1. Syntax — RFC-aware validation, so malformed addresses are caught immediately.
2. Domain (MX) — confirms the domain can actually receive mail and reveals the provider (Google Workspace, Microsoft 365, Zoho, Yandex…). Fast and cheap at any list size.
3. Live SMTP mailbox check (optional) — connects to the destination mail server (RCPT TO) and confirms whether that specific inbox exists, and detects catch-all domains that accept everything.

The mailbox check is opt-in, so you run the fast syntax + domain pass on everything and spend the extra time only on the lists that need mailbox-level certainty.

What you get for every address

• status — valid / risky / invalid / unknown
• deliverabilityScore — a transparent 0–100 confidence score, with a plain-English reasons array
• syntaxValid, hasMx, mxProvider
• mailboxExists and catchAll (when the live check is on), plus smtpConnected
• freeProvider (Gmail, Outlook…), roleBased (info@, sales@, support@), disposable (18,000+ throwaway domains)
• suggestedCorrection — typo rescue, e.g. [e-mail] → [e-mail]
• normalizedEmail — a de-duplication key that treats [e-mail] and [e-mail] as the same inbox

A sample row:

{
  "input": "[e-mail]",
  "email": "[e-mail]",
  "status": "valid",
  "deliverabilityScore": 95,
  "normalizedEmail": "[e-mail]",
  "mxProvider": "Google Workspace",
  "mailboxExists": true,
  "catchAll": false,
  "reasons": ["domain can receive mail", "mailbox confirmed to exist"]
}

Typo rescue saves real leads

Most validators silently drop gmial.com, yaho.com, or outlook.con as invalid — and you lose a lead who just fat-fingered their address. This one recovers the intended domain and hands it back as suggestedCorrection, so a typo becomes a usable contact instead of a deletion.

Built-in Email Finder

Don't have the address yet? Give the finder a name and a company domain. It builds the common corporate patterns (john.doe@, jdoe@, john@, jsmith@…) and, with the SMTP check on, verifies which one actually exists — skipping catch-all domains so you don't get false positives.

Input, one person per line:

Elon Musk, tesla.com
Bill Gates @ microsoft.com

Output per person:

{
  "mode": "finder",
  "name": "Elon Musk",
  "domain": "tesla.com",
  "candidates": ["[e-mail]", "[e-mail]", "[e-mail]", "[e-mail]"],
  "mostLikely": "[e-mail]",
  "email": "[e-mail]",
  "found": true,
  "verified": true,
  "reason": "mailbox verified via live SMTP check"
}

If the SMTP check is off or a server is unreachable, it still returns the ranked candidates and mostLikely (with verified: null), so the run is always useful.

Honest about the hard cases

Email verification has genuine edge cases, and this actor handles them without lying to you. Some mail servers greylist or rate-limit verification; catch-all domains accept every address. In those cases it returns its best signal from the domain/MX checks and marks the result risky/unknown instead of a false valid — and the run never fails. For maximum certainty on big lists, enable a proxy (auto for Apify Residential, or your own).

Inputs and filters

• Emails — one per line, or paste a whole CSV column; Name <[e-mail]> pastes are handled.
• Toggles — domain (MX) check on/off, live SMTP mailbox check on/off.
• Filters — return only valid / only deliverable, drop disposable, drop role-based, de-duplicate.
• Export — full JSON, CSV-friendly flat columns, or both. Dataset views include a ready-made "Deliverable (clean list)" table.

Turn on "return only deliverable" and you export just the addresses that are safe to send to — nothing else to clean up.

Who uses it

• Clean a lead list before a cold campaign — drop invalid and risky, keep your bounce rate low.
• Scrub a purchased or scraped list before importing to a CRM.
• Validate sign-up form input in bulk to stop fake and disposable signups.
• Find a decision-maker's email from a name and company domain.
• Protect sender reputation by removing role and catch-all addresses that are prone to spam traps.

Pricing

$1 per 1,000 results — you pay only for the addresses the actor returns, with no monthly subscription, no seat fees, and no API key. Use the only-valid / only-deliverable filters to return fewer records and pay for just the addresses you keep.

A note on responsible use

This tool checks whether addresses are valid and deliverable — it never sends mail, never logs in to any account, and never returns passwords or mailbox contents. Use it for legitimate list hygiene and B2B verification on addresses you have a lawful basis to process, and keep your sending compliant with GDPR, CAN-SPAM, and CCPA.

Bottom line

A clean list is the cheapest deliverability upgrade you'll ever make. Fast Email Validator & Verifier checks syntax, domain, and — when you want it — the live mailbox, rescues typos, finds missing addresses, and hands you a deliverable-only export, all for $1 per 1,000 with no API key. Verify before you send, and let the bounces be someone else's problem.

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What signal or output field would make your pre-send checks easier? Tell me and I'll look at adding it.