# Deliverability fundamentals

> Inbox placement is mostly authentication, consistent sending identity, engagement quality, and complaint control. SPF, DKIM, and DMARC are table stakes. Everything else is operational discipline.

Authentication, reputation, list hygiene, and inbox placement without mythology.

## Lessons

- [Authentication: SPF, DKIM, and DMARC](/lessons/authentication-spf-dkim-dmarc): The three DNS records every sending domain needs.
- [Inbox placement and reputation](/lessons/inbox-placement-and-reputation): Warmup, engagement, complaints, and mailbox provider expectations.

**Canonical:** https://emailmarketing.sh/courses/deliverability

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