Study first
Prepare for Email Deliverability Basics Quiz for Beginners
Use this short review before the quiz if you want to check the deliverability basics that affect whether marketing emails reach inboxes.
Authentication and sender trust
Mailbox providers use authentication and sending patterns to judge whether messages are trustworthy.
- Gmail requires all senders to set up SPF or DKIM.
- Bulk senders need SPF, DKIM, and DMARC.
- Authenticated messages are less likely to be rejected or marked as spam.
- Sending from a consistent identity helps recipients recognize messages.
Unsubscribe and complaints
Deliverability depends on whether recipients want the mail. Easy unsubscribe paths can reduce spam complaints.
- Bulk promotional messages to Gmail need one-click unsubscribe.
- Marketing messages should also include a clearly visible unsubscribe link.
- High spam rates can hurt inbox delivery.
- Gmail recommends keeping spam rates below 0.10% and avoiding 0.30% or higher.
Bounces and list quality
Bounces and inactive recipients are signs to review list quality. Healthy lists are built from people who asked to receive the messages.
- A hard bounce usually means a permanent delivery problem.
- A soft bounce usually means a temporary delivery problem.
- Purchased email addresses can create deliverability risk.
- Monitoring Postmaster Tools can help find sender reputation issues.