Switching to a new email service provider? Moving from one IP to another?
Or maybe you’ve just launched your service and are about to start emailing your subscribers for the first time?
In all these cases, warm-up is essential.
It’s the process of building trust with your subscribers first, because their reaction — opens, clicks, and replies — tells mailbox providers whether you’re a good sender or not.
Without warm-up, mailbox providers see you as an unknown sender, and unknown senders often land in spam.
📈 Why Warming Up Matters
Mailbox providers (Gmail, Outlook, Yahoo, etc.) evaluate every sender based on history and trust.
If you suddenly start sending thousands of emails from a new IP or domain, they think:
“Who is this sender? Why haven’t we seen them before? Could this be spam?”
The warm-up process solves this by starting with your most engaged subscribers.
If they react positively, mailbox providers notice — and begin to trust you.
It’s like moving into a new neighborhood — you start by meeting a few neighbors, earning goodwill, and then invite more people over.
How the Warm-Up Process Works
1️⃣ Start Small – Begin with your most engaged subscribers. Their positive interactions set the tone for mailbox providers.
2️⃣ Increase Gradually – Grow daily send volume by ~20–30% each step. Example: 200 → 260 → 340 → 440…
3️⃣ Keep Engagement High – Avoid sending to inactive contacts during warm-up. Low engagement sends the wrong signal.
4️⃣ Stay Consistent – Send at regular times; avoid erratic spikes.
5️⃣ Monitor Reputation – Use Google Postmaster, Microsoft SNDS, or EmailConsul to track signals and engagement.
⏳ Typical Warm-Up Timelines
• Small senders (up to 5k/day): 2–3 weeks
• Medium senders (5k–50k/day): 4–6 weeks
• High-volume senders: 8+ weeks
Patience is key — rushing risks deliverability damage that can take months to fix.
🚨 Common Warm-Up Mistakes
Sending too much too soon
Using purchased or scraped lists
Ignoring engagement metrics (opens, clicks, replies)
Pausing for long stretches (a “cold” IP may need to restart)
Skipping authentication records (SPF, DKIM, DMARC)
Mixing risky content too early (spammy words, heavy HTML, too many links)
🔥 Pro Tips
✅ Authenticate (SPF, DKIM, DMARC) before starting
✅ Segment your list — best contacts first
✅ Avoid spammy language or risky links
✅ Track results daily and adjust as needed
💡 Summary
Warm-up is your subscriber trust bootcamp.
Mailbox providers don’t decide you’re a good sender — your subscribers do.
When your most engaged audience reacts positively, mailbox providers see that signal and reward you with inbox placement.
Start small, grow steadily, keep engagement high, and avoid common mistakes.
Build trust with your subscribers first, and your email reputation will follow.