Glossary Archive

Sending email in controlled batches (groups) instead of all at once to manage throughput and reduce the risk of rate limiting/deferrals.

An automated email triggered by a recipient action or event (e.g., sign-up, browse, cart add, purchase).

Brand Indicators for Message Identification: a standard that can display a verified brand logo in supporting inboxes. Typically requires DMARC enforcement and a BIMI DNS record (and sometimes a certificate).

A list (or list provider) of IPs/domains associated with abusive sending. Often used as a reputation signal; depending on the list, it may lead to filtering or blocking.

A list of IPs or domains associated with spam/abuse. Mailbox providers and filters use blocklists to decide whether to reject, spam-folder, or throttle mail.

A blocklist (formerly commonly called a blacklist): a list of IPs or domains known for sending spam or malicious mail, used to filter or reject messages.

A non-delivery event where the receiving server rejects or cannot accept an email. Bounces are typically classified as hard (permanent) or soft (temporary).

An SMTP (or carrier) error response describing why a message could not be delivered or was deferred (e.g., 4xx temporary, 5xx permanent).

A U.S. law that sets rules for commercial email (e.g., identification, physical address, and a working opt-out/unsubscribe mechanism).

U.S. law governing commercial email requirements (e.g., truthful headers, a physical address, and a functioning opt-out/unsubscribe mechanism).