Best Email Warmup Tools (2026 Guide)

Why Warmup Matters

New email accounts have no reputation. Gmail, Outlook, and spam filters don't trust them.

Warmup builds trust by:

• Sending and receiving real emails

• Getting those emails opened, replied to, marked as important

• Building domain reputation gradually over 14+ days

Skip this step? Your campaigns fail before they start.

The 6 Best Warmup Tools in 2026

1. Smartlead Warmup — Best Built-In Option

Price: Included with Smartlead ($39+/mo)

What it does: Network of 20,000+ mailboxes exchanging emails. Auto-opens, replies, removes from spam.

Pros:

• No separate subscription needed

• Integrates directly with campaigns

• Decent network size

Cons: Only works with Smartlead sending. Limited customization.

Our take: If you're using Smartlead for sending, use their warmup. Simple.

2. Instantly Warmup — Best for Volume

Price: Included with Instantly ($37+/mo)

What it does: Largest warmup network (over 200,000 mailboxes). High email volume per day.

Pros:

• Huge network

• Fast warmup (can do 5,000+ emails/day)

• Automatic spam rescue

Cons: Quality of interactions varies. Still on shared infrastructure.

Our take: Good warmup, especially if you're already using Instantly. The network size helps.

3. Warmbox — Best Standalone Tool

Price: $19/mo (starter) | $49/mo (pro)

What it does: Dedicated warmup service with detailed reputation tracking.

Pros:

• Works with any ESP

• Good analytics dashboard

• Flexible warmup schedules

Cons: Extra cost on top of sending platform. Smaller network than built-in options.

Our take: Solid choice if your sending platform doesn't include warmup. The flexibility is worth the extra cost.

4. Mailreach — Best for Monitoring

Price: $25/mo per inbox

What it does: Warmup + deliverability testing in one tool. Shows exactly where emails land.

Pros:

• Seed list testing included

• Detailed inbox placement reports

• Blacklist monitoring

Cons: Gets expensive with many inboxes. Interface takes getting used to.

Our take: The monitoring features set this apart. Worth it for teams serious about deliverability.

5. Lemwarm — Best for Lemlist Users

Price: Included with Lemlist ($59+/mo)

What it does: Lemlist's built-in warmup network.

Pros:

• Seamless Lemlist integration

• Decent network size

• Auto-optimizes based on performance

Cons: Only works with Lemlist. Less control over settings.

Our take: If you're committed to Lemlist, use Lemwarm. Otherwise, there are better options.

6. Email Guard — Best for Agencies

Price: Custom pricing

What it does: Enterprise warmup + real-time inbox placement monitoring.

Pros:

• White-label options

• Advanced analytics

• Priority support

Cons: Not cheap. Overkill for small teams.

Our take: We use Email Guard for client monitoring. When you're managing thousands of inboxes, you need real-time visibility.

The BuzzLead Warmup Protocol

This is what we run for every new client:

• Days 1-3: 5 emails/day

• Days 4-7: 10 emails/day

• Days 8-10: 20 emails/day

• Days 11-14: 30 emails/day

• Day 15+: Full volume

We never skip this. Ever. Rushing warmup is how you torch domains.

The 75% Rule

Check inbox placement weekly. Tools like GlockApps or Email Guard show exactly where emails land.

If inbox placement drops below 75%:

1. Pause all sending immediately

2. Find the trigger (content, volume, or blacklist)

3. Fix the issue

4. Test again before resuming

This saved Green Clean's campaign. They went from 0.8% reply rate to 2.3% — generating $520K in pipeline.