Sender Reputation: This is based on the sender's history of email practices, like the frequency of emails sent and the number of complaints received. Content Quality: Algorithms evaluate the relevance and quality of email content. Avoiding spammy language and including personalized content can enhance deliverability. Engagement Rates: High open rates, click-through rates, and minimal unsubscribe rates signal to algorithms that recipients find your emails valuable. Authentication: Proper authentication protocols such as DKIM, SPF, and DMARC help verify the sender's identity.