What decides the inbox
Mailbox providers score sender reputation from authentication, sending behavior, and engagement. Poor authentication, sending too fast from a cold domain, spammy content, and low reply rates all push you toward the spam folder. A brand-new domain blasting volume is the fastest way to burn reputation.
Protecting it
Deliverability is protected by warming the domain, keeping volume measured, cleaning lists to cut bounces, and earning replies, which signal to providers that your mail is wanted. It is why a first cold email should ask for a reply, not carry a link or a hard pitch that trips filters.
Common questions
Why do my cold emails land in spam?
Usually weak authentication, sending too much too soon from a cold domain, high bounce rates, or content that looks promotional. Providers read all of these as signals to filter you out.
How do you improve deliverability?
Authenticate the domain (SPF, DKIM, DMARC), warm it up gradually, keep volumes sane, clean your list to reduce bounces, and design early messages to earn replies.