Deliverability
The probability that your email lands in the inbox rather than spam.
Published January 15, 2026 · By RAPID SMTP
Driven by authentication (SPF/DKIM/DMARC), sender reputation (IP + domain), list hygiene, engagement, and content. A healthy program lands 95%+ in the inbox.
Related terms
- SPF (Sender Policy Framework)A DNS record that lists which servers are allowed to send mail for your domain.
- DKIM (DomainKeys Identified Mail)A cryptographic signature added to every outbound email that proves it came from your domain.
- DMARCA DNS policy that tells receivers what to do when SPF or DKIM fail.
- IP warm-upGradually ramping send volume on a new IP so receivers build reputation for it.