How to Warm Up Email Accounts to Avoid Spam

Gradually increase sending volume on new email accounts to build sender reputation and improve deliverability.

Why warm-up is necessary

New email accounts have no sending history. Sending high volumes immediately signals spam behavior to email providers, causing:

• Emails landing in spam folders
• Account throttling or suspension
• Domain reputation damage
• Low open and reply rates

How warm-up works

Warm-up gradually increases sending volume over 2-4 weeks:

Enabling warm-up in 100Hires

1. Go to Settings > Email Carousel (https://app.100hires.com/settings/email-carousel)
2. Select the email account to warm up
3. Enable Automatic warm-up
4. System manages daily limits automatically

Automatic limit adjustment

With warm-up enabled:

• Daily sending limit starts low
• System monitors deliverability metrics
• Limits increase as reputation builds
• Adjusts down if problems detected

Manual warm-up strategy

If managing limits yourself:

Week 1

• Limit: 10-20 emails/day
• Send to engaged contacts (people likely to open)
• Monitor bounce rates

Week 2

• Limit: 30-50 emails/day
• Continue prioritizing quality recipients
• Check spam folder placement

Week 3

• Limit: 75-100 emails/day
• Expand to broader audience
• Review open rates

Week 4+

• Increase to normal sending volume
• Maintain consistent daily sending
• Monitor metrics continuously

Best practices

Send to engaged recipients first

• Start with warm leads who will open
• Opens and replies build reputation
• Avoid cold lists during warm-up

Maintain consistency

• Send every day, not in bursts
• Consistent volume signals legitimacy
• Gaps can reset progress

Monitor deliverability

Watch for warning signs:

• Bounce rate > 5%
• Open rate < 10%
• Sudden drop in engagement
• Emails appearing in spam

Avoid spam triggers

During warm-up, be extra careful:

• No spam words in subject lines
• Personalize content
• Include unsubscribe option
• Use clean email lists

Signs warm-up is working

• Steady or improving open rates
• Low bounce rates
• Recipients finding emails in inbox
• No spam complaints
• Gradual increase in sending capacity

Troubleshooting

High bounce rate

• Verify email addresses before sending
• Use ZeroBounce integration
• Remove invalid addresses

Low open rates

• Improve subject lines
• Send at optimal times
• Segment your audience

Emails going to spam

• Reduce volume
• Improve content quality
• Check domain authentication (SPF, DKIM)

Updated on: 26/12/2025