What We Check

Syntax Validation

Checks RFC 5321 and RFC 5322 compliance. Validates the local part (max 64 characters), domain format, and TLD presence. Rejects addresses with invalid characters, consecutive dots, or missing components.

Role Account Detection

Flags addresses whose local part matches one of 100+ role-based prefixes — admin, support, sales, noreply, info, billing, hr, legal, and many more. Role accounts are typically mailing lists or ticketing systems, not individual inboxes.

Disposable Email Detection

Checks the domain against a continuously updated database of 121,000+ disposable email providers (Mailinator, Guerrilla Mail, 10-Minute Mail, etc.). Also performs a second-pass check of the MX infrastructure to catch domains that relay through known DEA hosts.

Free Email Provider Identification

Identifies addresses from free consumer providers (Gmail, Yahoo, Outlook, Hotmail, AOL, iCloud, ProtonMail, etc.). While not a disqualifying signal, this flag helps segment consumer vs. business addresses.

DNS / MX Record Lookup

Resolves MX records for the domain with automatic retry on transient DNS errors. Detects parked domains (100+ parking service MX patterns), inactive domains, and common domain typos (e.g. gmial.com → gmail.com). Results are cached for 5 minutes per domain to avoid redundant lookups during bulk verification.

Honeypot & Spamtrap Detection

Scans the local part for 30+ spamtrap patterns (spamtrap, honeypot, spamcop, spamhaus, pristine, recycled-trap, etc.) and 10+ fake/test patterns (test, fake, example, temp, dummy). These addresses are seeded to catch bulk senders with poor list hygiene.

SMTP Mailbox Validation

Connects to the receiving mail server, issues an EHLO/HELO handshake, and probes the mailbox with RCPT TO. Detects firewall-blocked port 25, catch-all configurations, deferred verification gateways (Microsoft 365, Google Workspace, ProofPoint), and temporary greylisting. Uses rotating sender domains to minimise IP-based blocking.