Glossary

Short definitions for terms you will see in the curated list and docs.

A recurring email (or series) sent to subscribers, usually with editorial content, links, or product updates.

ESP (Email Service Provider)

A platform used to send marketing or transactional email (for example Mailchimp, ConvertKit, Beehiiv).

Practices that grow a permission-based subscriber list: lead magnets, landing pages, forms, referrals.

A subscriber explicitly agrees to receive email. Double opt-in confirms via a second email click.

Whether messages reach the inbox (vs spam/promotions). Involves authentication (SPF/DKIM/DMARC), reputation, and engagement.

Classic newsletter metrics. Privacy changes (for example Apple Mail Privacy Protection) make opens less reliable; clicks and conversions matter more.

How a newsletter earns: subscriptions, sponsorships, ads, affiliates, products, donations.

Automated, user-triggered messages (receipts, password resets) — distinct from bulk newsletters, though tools often overlap.

Email bodies built with constrained HTML/CSS. Often assembled with frameworks (MJML, Maizzle) or ESPs' editors.