Email Verifier without SMTP: Syntax, MX, Disposable, Typos

Clean an email list without ever talking to a mail server. This Actor never sends a message and never opens an SMTP connection. That makes it fast, safe for your IP reputation and invisible to the recipients' mail servers.

Be clear about what this is

Without SMTP nobody can prove that a mailbox exists. This Actor scores deliverability risk from public facts: is the address well formed, can the domain receive mail at all, is it a throwaway domain, a shared role mailbox or a likely typo. An address marked valid-looking can still bounce if the mailbox was deleted. An address marked invalid will not receive mail.

Checks per address

check	how
Syntax	practical subset of RFC 5322 (dot-atom local part up to 64 characters, domain up to 253, no IP literals, no quoted local parts)
Normalization	trims spaces and mailto:, unwraps Name <a@b.de>, lowercases the domain, converts international domains to punycode (müller.de to xn--mller-kva.de)
Typos	edit distance against common providers (gmail, googlemail, gmx, web.de, t-online, outlook, hotmail, live, yahoo, icloud, posteo, freenet, proton, aol and more) and common TLD slips such as .con or .dee
Domain	MX records over DNS over HTTPS (Google, Cloudflare as fallback), A and AAAA as implicit MX, null MX (RFC 7505), domain does not exist (NXDOMAIN)
Disposable	bundled snapshot of the open disposable-email-domains list, subdomains included
Role address	info, kontakt, contact, office, support, sales, noreply, admin, buero, verwaltung, rechnung, bewerbung and about 100 more
Free mail	gmail, gmx, web.de, t-online, yahoo, outlook, hotmail, icloud, proton, posteo, freenet, mail.de and more
Mail provider	from the MX hosts: Google Workspace, Microsoft 365, IONOS, Strato, Hostinger, Zoho, Proton, GMX and web.de, T-Online, Yahoo, iCloud, Mimecast, Proofpoint and more

DNS answers are cached per domain during a run, so 10,000 addresses at the same company cost one lookup.

Output per address

field	meaning
email	normalized address (domain lowercased and in punycode)
status	valid-looking, risky or invalid
score	0 to 100, higher is safer to send to
reasons, reasonCodes	every finding as a sentence and as a stable code
didYouMean	suggested correction for a likely typo
isDisposable, isRoleBased, isFreeProvider	flags
domainExists, hasMx, nullMx, implicitMx, mxRecords	DNS facts
mailProvider	who hosts the mailbox, if recognizable

How the status is decided

• invalid (score 0): broken syntax, domain does not exist, null MX, or the domain has neither MX nor A/AAAA records.
• risky: disposable domain, likely typo, DNS errors, mail only via implicit MX, or a score below 70.
• valid-looking: everything checked looks fine. Role addresses lose 15 points and stay valid-looking when nothing else is wrong.

Input

A list of addresses, a pasted text block (one per line or separated by commas or semicolons), or both. Duplicates are removed (case-insensitive). Each check can be switched off.

Pricing

You pay per checked address. Addresses with broken syntax count as checked, since that is a result. Internal errors (for example both DNS services unreachable) are not charged.

Limits

• No SMTP: mailbox existence and catch-all domains cannot be detected.
• The disposable list is a snapshot (source below). New throwaway domains appear daily.
• Provider detection only knows the hosts listed above; others return null.

Data source

Disposable domains: disposable-email-domains/disposable-email-domains, CC0 1.0 (public domain), snapshot of commit e4f0910 from 2026-10-23 with 9,927 domains.

Not affiliated with Google, Microsoft, Cloudflare or any mail provider named here.

FAQ

Does it send an email or connect to the mail server? No. It never opens an SMTP connection and never sends a message. It only checks syntax, bundled lists and public DNS records.

What am I charged for? One event per checked address. Addresses with broken syntax count as checked because the verdict is a result. Internal errors, for example when both DNS over HTTPS services are unreachable, are pushed as items with an error field and are not charged.

Can it tell me if a mailbox exists or if a domain is catch-all? No. Without SMTP that cannot be detected. A valid-looking address can still bounce if the mailbox was deleted.

What happens when a DNS lookup fails? If the resolvers answer with an error such as SERVFAIL, the address gets the reason code dns_error and the status risky, because deliverability is unknown. If neither Google nor Cloudflare DNS can be reached at all, the address is returned as an error item.

How many addresses can one run handle? Up to maxEmails (default 100,000, maximum 1,000,000) after duplicates are removed. DNS answers are cached per domain, so many addresses at the same domain need only one lookup.

Use with AI agents (MCP)

This Actor works as a tool for Claude, ChatGPT, Cursor and other MCP clients through the Apify MCP server. Add only this Actor:

https://mcp.apify.com?tools=webify-lab/email-verifier-no-smtp

On first use the server signs you in with OAuth. Alternatively send the header Authorization: Bearer <APIFY_TOKEN>. Agents on the default Apify MCP setup can also find this Actor with search-actors and run it with call-actor. Pricing is the same as in Apify Console: you pay per result.