IP warmup
IP warmup is the process of gradually increasing sending volume from a new or dormant dedicated IP address while maintaining high engagement, so mailbox providers build trust in that IP before it sends full volume. Sending large volume from a cold IP triggers throttling or spam-foldering because providers have no history to trust.
How it works
You follow a ramp schedule — starting with a small daily volume to your most engaged recipients and increasing it over days or weeks — so the IP accumulates a positive sending history. Providers watch bounce and complaint rates during the ramp and adjust how much they trust the IP.
Why it matters
A cold dedicated IP with no reputation is treated with suspicion; blasting volume from it lands mail in spam or gets it throttled. Warming the IP establishes the track record needed to reach the inbox at scale, similar to warming a new mailbox or domain.
How Autocloz handles it
Autocloz applies warmup ramps and adaptive daily ceilings to sending identities so volume grows only as fast as reputation allows — the same discipline that protects mailboxes and domains applies to sending capacity generally.
FAQ
How long does IP warmup take?
Typically two to eight weeks depending on target volume, starting small and roughly increasing daily sends while watching bounce and complaint rates. Higher target volumes need longer, more gradual ramps to avoid tripping provider throttles.
Do I need a dedicated IP for cold email?
Not always. Dedicated IPs suit consistent high volume and give you full control of reputation, but they require warmup and steady sending. Lower-volume senders often do fine on well-managed shared IPs and should focus on domain reputation and warmup instead.
Related terms
Mailbox warmup is the practice of gradually increasing a new email account's sending volume while generating positive engagement (opens, replies, moving mail out of spam) so mailbox providers build trust in the sender before real campaigns ramp up.
Sender reputation is the trust score mailbox providers assign to your sending domain and IP based on how recipients react to your mail — opens, replies, spam complaints, bounces and spam-trap hits. A high reputation lands you in the inbox; a low one routes you to spam or blocks you.
Inbox placement rate (IPR) is the percentage of delivered emails that actually land in the primary inbox rather than the spam/junk folder or a tab like Promotions. Unlike 'delivered' (which only means accepted by the server), IPR measures whether a human is likely to see the message.
Domain reputation is the trust score mailbox providers assign to your sending domain based on its authentication, sending history, engagement and complaint signals. Unlike IP reputation, it follows the domain wherever it sends, which is why it has become the dominant reputation signal as senders share pooled IPs.