Email Warm-Up Strategy: How to Build Domain Reputation from Zero

01 What is Email Warming Up?

Email warming up is the process of gradually increasing your sending volume from a new domain or IP address over several weeks. The goal is to build a positive sending history and establish trust with inbox providers before sending at full volume.

Inbox providers like Gmail, Outlook, and Yahoo track your sending history. A brand new domain or IP that suddenly starts sending thousands of emails has no history — and looks exactly like a spammer. By ramping up slowly with high-quality, engaging content, you prove to ISPs that you are a legitimate sender.

02 When Do You Need to Warm Up?

You need to warm up in these situations:

• New sending domain — you've registered a new domain and are sending from it for the first time
• New subdomain — even a subdomain like email.yourcompany.com needs its own warm-up
• New dedicated IP address — dedicated IPs on BouncePro Premium plan need warming up
• Switching ESPs — moving from another platform to BouncePro requires warming up your domain on our infrastructure
• Long sending gap — if you haven't sent in 3+ months, a partial warm-up may be needed

03 Domain Warm-Up vs IP Warm-Up

There are two types of reputation to build — and in 2026, domain reputation is more important than IP reputation:

Domain Warm-Up

Your sending domain (e.g. yourcompany.com) builds its own reputation with inbox providers — independent of the IP you use. Domain reputation is increasingly the primary signal Gmail uses. All BouncePro users need to warm up their sending domain.

IP Warm-Up

Your sending IP address also has its own reputation. On BouncePro's shared plans, you send through our managed shared IP pools — we maintain these IPs and handle their reputation for you. If you upgrade to a dedicated IP (Premium plan), that IP starts with zero history and needs its own warm-up process.

04 Warm-Up Schedule

Follow this schedule for a new domain. If you're warming up a dedicated IP, use the same schedule but apply it to IP send volume specifically.

Always send to your most engaged subscribers first — people who regularly open and click your emails. This generates the positive engagement signals that build reputation fastest.

05 What to Send During Warm-Up

The content you send during warm-up is as important as the volume. You need strong engagement signals to build reputation quickly.

Best Content for Warm-Up

• Your welcome email series — new subscribers are most engaged; they expect and look forward to these
• Your best-performing content — use campaigns with historically high open and click rates
• Personalized, relevant content — the more targeted and relevant, the higher the engagement
• Content that prompts a reply — replies are the strongest positive reputation signal you can generate

What to Avoid During Warm-Up

• Mass promotional blasts to your entire list
• Sending to cold, unengaged segments
• High-image, low-text emails that may trigger spam filters
• Sending to any purchased or unverified lists
• Sudden volume spikes — always increase gradually and predictably

06 Monitoring Your Warm-Up Progress

Monitor these signals daily during the warm-up period:

• Open rate — should stay above 20% throughout warm-up. A drop signals ISPs may be filtering.
• Bounce rate — keep under 2%. Any spike means list quality issues to fix immediately.
• Spam complaint rate — must stay under 0.1%. Above 0.3% means immediate pause.
• Google Postmaster Tools — check domain reputation weekly. Should move from Low → Medium → High over the warm-up period.
• Spam folder placement — send test emails to Gmail, Outlook, and Yahoo accounts and check where they land.

07 Warm-Up Checklist

Related: Sender Reputation Guide · Spam Trap Detection · Deliverability Hub