Email deliverability basics
Passing SPF, DKIM and DMARC does not guarantee inbox placement. Deliverability depends on whether mailbox providers trust your sending behaviour and your recipients actually want the mail.
Sender reputation
Mailbox providers build their own view of trust using IP reputation, domain reputation, complaint rates, spam trap hits, bounce patterns and consistency of sending behaviour.
Engagement and list quality
High complaint rates, repeated sending to dead addresses and lack of real engagement make future delivery harder. Good list hygiene matters as much as technical setup.
Content and structure
Content alone is not usually the main cause of failure, but misleading subject lines, aggressive formatting, suspicious URLs and poor audience matching can all make a bad situation worse.
What to monitor
- Spam complaint rate
- Bounces and invalid addresses
- Opens and clicks, interpreted carefully
- Blocklist events
- Per-provider inbox placement patterns