What is Email Warmup?
TL;DR
A process that raises a new sending account's reputation by gradually increasing volume from a small base, with accounts sending/replying to each other so providers see a 'healthy sender.'
Email Warmup: Definition & Explanation
Email warmup is the preparation process of raising a sender's reputation before sending cold email from a newly prepared email account or domain. Instantly, Smartlead, Warmbox, and mailreach offer it as a dedicated feature.\n\nEmail providers (Gmail, Outlook, etc.) tend to treat an account that suddenly starts sending in volume as spam and keep it out of the inbox. In warmup, you start with a few emails a day and gradually increase volume over several weeks. In many tools, warmup email accounts automatically send to each other, simulating opens, replies, and rescues from the spam folder, teaching providers that 'this account is a healthy sender being received favorably by humans.'\n\nThis improves [[cold-email-deliverability]] so your real cold emails reach the inbox more reliably. Warmup is run not only right after opening an account but continuously at a low volume to maintain reputation. The standard practice is to combine it with a separate sending domain and SPF/DKIM/DMARC settings.