Introduction

Welcome to Email Domain 101.

This course will teach you the basics of Email Domain Management to help you understand how email works and better send emails at scale.

Key terms

• Deliverability: Put simply, deliverability is the practice of exploring the spam filter. It is not the practice of avoiding the Promotions tab, the best friend you never knew you had.
• Inbox provider: an inbox provider is the receiving system that accepts your emails. Common inbox providers are Gmail, Outlook, Yahoo, and Hotmail, but there are countless niche providers across the internet.
• Batch-and-blast: Any bulk sending sent in large batches. This is often in the form of a Newsletter, or messages sent via batch API.
• ESP: Email service provider. Resend is an example of an ESP.

What’s ahead

Across the next few lessons, we’ll walk through:

• Mail categorization: how inbox providers bucket compliance, notifications, and marketing mail, and why getting this right shapes everything that follows.
• Transactional provisioning: what qualifies as transactional, when an unsubscribe link is legally required, and where automations can quietly trip you up.
• Choosing your subdomains: splitting transactional from bulk so a bad newsletter day can’t take your password resets down with it.
• DNS setup: DKIM, SPF, DMARC, link tracking, and the records your ESP will ask you to publish.
• Domain Warming: the practice of sending a small number of test emails to your domain to warm it up and avoid being flagged as spam.
• Domain Reputation: the practice of keeping your domain reputation healthy by avoiding spam and avoiding being blacklisted.

Along the way you’ll pick up the vocabulary and the practical instincts that separate “messages that arrive” from “messages that land in the inbox.”