Email Verification

Email deliverability is the ability of your messages to reach the recipient's inbox rather than the spam folder or a hard bounce. It depends on authentication (SPF/DKIM/DMARC), sender reputation, list quality, content, and engagement. Verified data and a warmed-up sending domain are the foundation of strong deliverability.

A catch-all (or accept-all) domain accepts mail to any address at the domain, even ones that don't exist, so an SMTP check can't conclusively verify a specific mailbox. Catch-all addresses carry elevated bounce risk and are typically scored as a separate, lower-confidence tier rather than treated as fully valid.

Bounce rate is the percentage of sent emails that fail to deliver. Hard bounces are permanent failures (invalid address); soft bounces are temporary (full mailbox). High bounce rates signal poor list quality to mailbox providers and damage sender reputation, which is why verifying addresses before sending is essential.

Sender reputation is a score mailbox providers assign to a sending domain and IP based on history — bounce rates, spam complaints, engagement, and authentication. A strong reputation lands mail in the inbox; a poor one routes it to spam. It is built slowly through warmup and clean lists, and damaged quickly by sending to unverified addresses.

Cold email is unsolicited but targeted B2B outreach to prospects who haven't engaged before, aimed at starting a conversation. Effective cold email depends on verified data, strong deliverability, relevant personalization, and compliance with regulations like CAN-SPAM and GDPR. It is a data problem as much as a copy problem.