IP Warm-Up

What is IP Warm-Up?

IP warmup is the gradual process of increasing email sending volume from a new or dormant IP address to establish a positive sender reputation with mailbox providers. The goal is to build trust by demonstrating you're a legitimate sender with engaged recipients.

How It Works:
Instead of sending thousands of emails immediately from a new IP, you start small and slowly increase volume over weeks. This allows mailbox providers to observe your sending patterns and recipient behavior, building reputation gradually.

Why IP Warm-Up Matters

Without Warmup:

• Sudden high volume from new IP looks like spam
• Mailbox providers block or filter aggressively
• Recovering from poor first impression takes weeks
• Campaigns fail before they start

With Warmup:

• Establish positive sending patterns
• Build reputation through good engagement
• Achieve desired inbox placement rates
• Protect long-term sending capability

In 2026, with mailbox providers using AI to detect suspicious patterns, proper warmup is more important than ever. Cutting corners damages reputation immediately.

Warm-Up Timeline

Typical Schedule:

Week	Daily Sends	Total Weekly
Week 1	50-100	500-700
Week 2	200-300	1,500-2,000
Week 3	500-700	3,500-5,000
Week 4	1,000-1,500	7,000-10,000
Week 5+	Gradual increase to target volume

Important Notes:

• Timeline varies by expected volume
• High-volume senders need longer warmup
• Monitor engagement and adjust accordingly
• Never skip ahead—sudden spikes trigger spam filters

Warm-Up Best Practices

Start with Your Best List:

• Most engaged subscribers first
• Past customers who opened/clicked recently
• People who explicitly opted in
• Avoid cold or purchased lists during warmup

Monitor Key Metrics:

• Spam complaints (must stay under 0.1%)
• Bounce rate (must stay under 1%)
• Open rates (should be 20%+)
• Inbox placement (monitor across providers)

Maintain Consistency:

• Send every day during warmup
• Keep volume consistent within each week
• Avoid skip days then volume spikes
• Same sending times each day

Engagement Matters Most:
Mailbox providers care about recipient behavior. High engagement (opens, clicks, replies) builds reputation faster than volume alone.

Warm-Up Automation Tools

Sales Engagement Platforms:

• Outreach, Salesloft, Groove: Built-in warmup features
• Automatically ramp volume while monitoring health
• Pause if reputation metrics decline

Dedicated Warmup Tools:

• Mailwarm, Lemlist, Instantly: Peer-to-peer warmup
• Automated conversations between inboxes
• Build reputation through natural reply chains

Common Mistakes

• Starting cold outreach before warmup completes
• Skipping warmup entirely (immediate high volume)
• Warming up with purchased or scraped lists
• Sudden volume increases during warmup
• Not monitoring engagement metrics during warmup
• Inconsistent sending patterns

Key Takeaways

• IP warmup gradually increases volume to build sender reputation
• Typical warmup: 2-4 weeks to reach target volume
• Start with most engaged subscribers
• Monitor spam complaints, bounces, and engagement daily
• Never skip warmup—it causes lasting reputation damage