How to warm up a new domain
Jesse Hanley
Founder • Bento
📧 ➜ 📬 ➜ 📥 INBOX SUCCESS!
╰─────────────────────────╯
Domain Warming Process
Starting with a new domain for email? Finally got that shiny new dot com? Planning to start sending waitlist emails for your new app?
Then you need start planning your domain warm up strategy.
Skip this step, and you risk your emails landing in spam. Do it right, and you'll slide into peoples inboxes without a sweat.
Here's everything you need to know about domain warming, with a proven 30-day process that works.
Quick Summary: What You Need to Know
┌─────────────────────────────────────────┐
│ 🏗️ DOMAIN WARMING ESSENTIALS │
├─────────────────────────────────────────┤
│ Timeline: 30 days minimum │
│ Start: 10-100 emails/day │
│ End goal: 1,000+ emails/day │
│ Critical: First 2 weeks crucial │
└─────────────────────────────────────────┘
Domain warming is the process of gradually building your new domain's email reputation with ISPs (Gmail, Yahoo, Hotmail, etc) by starting with low sending volumes and slowly increasing over a period of time.
All newly registered domains, or domains that recently started sending email for the first time, are treated suspiciously. The ISPs need to gather data on your new domain (complaint rate, engagement metrics ...) to ensure that this domain's emails are safe to put into the inbox of their users.
This process can be very touch and feel depending on the size of your list, so if you are dealing with a lot of email volume we recommend talking with your email service provider or hiring a deliverability consultant to ensure it's executed perfectly.
What is Domain Warming?
Domain warming is like introducing yourself to a new neighborhood.
You don't show up throwing a massive party on day one—you start small, meet a few neighbors, build relationships, and gradually expand your social circle.
Day 1: 🏠 → 👋 (meet 2-3 neighbors)
Day 7: 🏠 → 👋👋👋 (small gathering)
Day 30: 🏠 → 🎉 (neighborhood party!)
In email terms, domain warming means:
- Starting with small daily volumes (10-100 emails)
- Gradually increasing sends based on feedback over 30 days
- Putting your best food forward by sending to users who love you
- Building a positive reputation with email providers
When Do You Need Domain Warming?
You need to warm up your domain when:
✅ Brand new domain - never sent email before
✅ Major rebrand - old-company.com → new-company.com
✅ New subdomain - adding newsletter.company.com
✅ Long dormancy - domain dormant 6+ months
✅ Volume scaling - jumping from 100 to 1,000+ emails/day
Really? But I'm Just Switching TLDs ...
Gmail, Yahoo, and other ISPs don't know that you're switching domains or going through a major rebrand.
To them, all they see is a new domain emailing thousands of people for the first time out of the blue.
That's why it's important to send slow again and let ISPs gather information to show that yes, you are a good sender.
Domain Warming vs. IP Warming: What's the Difference?
While related, these are different processes:
┌─────────────────┬─────────────────────────────────────────┐
│ Domain Warming │ Builds reputation for your domain name │
│ (what we focus) │ Required for new domains │
│ │ 30-day process │
├─────────────────┼─────────────────────────────────────────┤
│ IP Warming │ Builds reputation for your IP address │
│ (handled by │ Required for dedicated IPs (shared are │
│ platforms) │ usually already warmed) │
│ │ +90 day process │
└─────────────────┴─────────────────────────────────────────┘
When sending on a platform like Bento, you don't need to worry about IP warming as we handle it for you via our managed network.
If you have a dedicated IP address on Bento, our team will help warm that up alongside you.
Why Domain Warming Matters
Whilst there are instances where domain warmup is not required, the times where it is required are usually high stakes.
For example, you have a large email list that drives revenue for the business or you have tens of thousands of users waiting for you to launch but haven't contacted them for months.
What Happens If You Skip Domain Warming
⚠️ DANGER ZONE: SKIPPING DOMAIN WARMING ⚠️
┌─────────────────────────────────────────────┐
│ 📧 ➜ 🗑️ Emails → Spam folders │
│ 📈 ➜ 📉 High bounce rates │
│ 🚫 ➜ ❌ Blocked by providers │
│ 💰 ➜ 💸 Wasted marketing spend │
└─────────────────────────────────────────────┘
Long-term damage:
- Reputation takes months to recover
- Blacklist inclusion
- Customer trust erosion
- Lost revenue opportunities
Real Example: The Cost of Skipping
We've seen this happen many times on our network when a customer will acquire a new domain, like a .com, and immediately email their newsletter to their entire list. Open rates plummet and a ticket is open freaking out. Whilst it's recoverable, it's a lot of work and a lot of wasted time by not following the process and taking it slow.
What Happens When You Do It Right
🚀 SUCCESS TIMELINE:
Week 1-2: 🏗️ Building foundation trust
📊 95%+ delivery rates
📈 High open rates from familiar contacts
Week 3-4: 📈 Scaling with confidence
🎯 Expanding to larger audiences
✅ Maintaining strong inbox placement
Month 2+: 🎉 Sustainable sending
⚡ Reliable delivery at scale
💪 Strong domain reputation
📊 Predictable campaign performance
The 30-Day Domain Warming Timeline
Here's your week-by-week roadmap to domain warming success for a small email list:
📅 DOMAIN WARMING TIMELINE
╭─────────────────────────────────────────────────────────╮
│ Week 1 │ Week 2 │ Week 3 │ Week 4 │
│ 10-100 │100-200 │200-500 │500-1K+ │ emails/day
│ 👥🔥 │ 👥📧 │ 👥📬 │ 🌍📨 │
│ Team │ Warm │ Active │ Full │
│ Only │ Subs │ List │ Scale │
╰─────────────────────────────────────────────────────────╯
Week 1: Foundation Building (Days 1-7)
Daily volume: 10-100 emails Focus: High engagement from personal contacts
🎯 WEEK 1 TARGETS:
┌─────────────────┐
│ Open rates: 40%+│
│ Reply rates: 5%+│
│ Spam: 0% │
└─────────────────┘
Day 1-3:
- Send to internal team (colleagues, personal accounts)
- Send to friends and family who expect your emails
- Focus on emails that will definitely be opened
Day 4-7:
- Start using it for a few low volume transactional emails like magic links (where people will hunt to find them)
Week 2: Expanding the Circle (Days 8-14)
Daily volume: 100-200 emails Focus: Engaged users only
🎯 WEEK 2 TARGETS:
┌─────────────────┐
│ Open rates: 35%+│
│ Reply rates: 3%+│
│ Spam: <0.1% │
└─────────────────┘
What to send:
- Switch over your welcome sequences to use your new domain
- Switch more transactional emails to the new domain (order confirmations, etc.)
Week 3: Building Momentum (Days 15-21)
Daily volume: 200-500 emails Focus: Broader subscriber base, maintaining engagement
🎯 WEEK 3 TARGETS:
┌─────────────────┐
│ Open rates: 30%+│
│ Reply rates: 2%+│
│ Spam: <0.1% │
└─────────────────┘
Expansion strategy:
- Split your newsletter into highly engaged users (new domain) and everyone else (old domain)
- Send the newsletter SLOWLY over a few days if you can
- Continue transactional emails
Week 4: Full Throttle (Days 22-30)
Daily volume: 500-1,000+ emails Focus: Complete subscriber base, monitoring metrics closely
🎯 WEEK 4 TARGETS:
┌─────────────────┐
│ Open rates: 25%+│
│ Reply rates: 1%+│
│ Spam: <0.1% │
└─────────────────┘
Final phase:
- Send to your full engaged subscriber list
- Launch broader marketing campaigns
- Monitor reputation metrics closely
- Adjust volume based on performance
- IMPORTANT: Send as slow as you can stomach for larger sends
Volume Progression Chart
📊 DAILY VOLUME PROGRESSION
Day 1-7: ████ (50-100 emails/day)
Day 8-14: ████████ (100-200 emails/day)
Day 15-21: ████████████ (200-500 emails/day)
Day 22-30: ████████████████████ (500-1,000+ emails/day)
└─────────────────────┘
Volume Scale
Scaling Domain Warmup for Large Lists (100k+ Contacts)
Got a large email list and need to switch domains?
The standard 30-day approach won't work—you need a different strategy entirely. Here's how to warm a new domain when you have tens of thousands (or hundreds of thousands) of contacts.
🏢 ENTERPRISE-LEVEL DOMAIN WARMING
╭─────────────────────────────────────────────╮
│ 📊 100K+ Contacts = Different Rules │
│ │
│ ⚠️ Standard 30-day timeline = FAILS │
│ ✅ 60-90 day strategy = SUCCEEDS │
│ │
│ 🎯 Segment → Stagger → Scale │
╰─────────────────────────────────────────────╯
The Challenge with Large Lists
Why standard warming fails:
- 100k contacts can't be warmed in 30 days as there will be too much total daily volume
- Engagement rates naturally drop with larger, less-targeted sends
- One bad campaign can tank your reputation across the entire list
- List hygiene issues become amplified at scale
The solution: Segment, stagger, and scale methodically.
The 60-90 Day Large List Strategy
For lists over 50k contacts, plan for a 60-90 day warming period:
📈 LARGE LIST TIMELINE (60-90 DAYS)
Phase 1: Foundation (Days 1-30)
Follow the standard warming timeline with your most engaged segments only. Limit your daily volume to 1,000 emails per day. Continue sending most of your emails using your old domain. For broadcast emails, batch them into hourly batches so they are spread out (Gmail prefers this). We **do not recommend** ever exceeding 5,000 emails per day on new domains ever.
Phase 2: Expansion (Days 31-60)
Gradually add larger segments while monitoring metrics closely. Increase your daily volume by 500 per day but monitor engagement rates closely. If you find that your engagement rates are dropping, you may need to reduce your volume.
Phase 3: Full Scale (Days 61-90)
Transition remaining contacts and optimize for full volume. Increase your daily volume in increments of 5,000 emails per day but monitor engagement rates closely. If you find that your engagement rates are dropping, you may need to reduce your volume.
It's mostly touch and feel, but you should be able to get to 100k contacts per day by the end of 90 days especially if you are sending on a good network and healthy IPs.
Step 1: Segment Your Large List Strategically
🎯 TIER SEGMENTATION STRATEGY
Tier 1: VIP Warmers (Days 1-14) 🔥
├─ Recent purchasers (last 30 days)
├─ High email engagers (last 5 emails)
├─ Team members and business contacts
└─ Size: 1,000-5,000 contacts max
Tier 2: Engaged Subscribers (Days 15-30) 📧
├─ Opened emails in last 60 days
├─ Clicked links in last 90 days
├─ Recent sign-ups (last 6 months)
└─ Size: 5,000-15,000 contacts
Tier 3: Active But Cooler (Days 31-45) 📬
├─ Opened emails in last 6 months
├─ No recent clicks but still engaged
├─ Longer-term subscribers with some activity
└─ Size: 15,000-30,000 contacts
Tier 4: The Rest (Days 46+) 📨
├─ Remaining engaged contacts
├─ Older subscribers with minimal recent activity
└─ Size: Remaining contacts
Tier 5: Dead Contacts (Days 1-30) 💀
└─ Consider sunsetting these contacts.
Step 2: The Parallel Domain Strategy
Don't abandon your old domain immediately. Run both domains in parallel:
🔄 PARALLEL DOMAIN MIGRATION STRATEGY
Month 1: New Domain ████░░░░░░ 10% | Old Domain ████████████████████████████████████ 90%
Month 2: New Domain ████████████████ 40% | Old Domain ████████████████████████ 60%
... and if it goes well ...
Month 3: New Domain ████████████████████████████████ 80% | Old Domain ████████ 20%
Month 4+: New Domain ████████████████████████████████████████ 100% | Old Domain ░░░░ 0%
Benefits:
- Maintains deliverability during transition
- Provides fallback if new domain has issues
- Gradual subscriber migration
Step 3: Modified Volume Scaling
Large list daily volumes:
🚀 LARGE LIST VOLUME PROGRESSION
Days 1-14: ██████ (1,000-2,000 emails/day) Tier 1 only
Days 15-30: ████████████ (3,000-5,000 emails/day) Tier 1 + 2
Days 31-45: ████████████████████ (8,000-15,000 emails/day) + Tier 3
Days 46-60: ████████████████████████████████ (20,000-40,000 emails/day) + Tier 4
Days 61+: ████████████████████████████████████████ (Full volume as needed)
└─────────────────────────────────────────┘
Scale Progression
Step 7: The Subdomain Strategy
For very large lists (250k+), consider multiple subdomains:
🏗️ SUBDOMAIN ARCHITECTURE
newsletter.company.com 📰 ➜ Weekly newsletters
offers.company.com 🎁 ➜ Promotional campaigns
updates.company.com 📢 ➜ Product updates
support.company.com 🛠️ ➜ Transactional emails
Benefits: Risk isolation | Specialized warming | Redundancy | Easy management
Real Example: 100k List Migration
📊 CASE STUDY: E-COMMERCE SUCCESS
Company: E-commerce with 100k subscribers
Challenge: Rebranding from old-store.com → new-brand.com
Timeline: 90 days
Success Formula:
┌─────────────────────────────────────────────┐
│ Days 1-30: ✅ 5k most engaged customers │
│ Days 31-60: ✅ +25k in hourly batches │
│ Days 61-90: ✅ Remaining 70k gradually │
│ Cleaned: ❌ Removed 30k unengaged │
└─────────────────────────────────────────────┘
Common Large List Mistakes
❌ AVOID THESE COSTLY MISTAKES:
┌─────────────────────────────────────────────┐
│ ❌ Trying to warm 100k contacts in 30 days │
│ ➜ Creates massive volume spikes │
│ ➜ Destroys engagement rates │
│ ➜ Triggers ISP spam filters │
└─────────────────────────────────────────────┘
┌─────────────────────────────────────────────┐
│ ❌ Not cleaning the list first │
│ ➜ Bad contacts hurt reputation │
│ ➜ Magnifies problems at scale │
│ ➜ Wastes warming "budget" │
└─────────────────────────────────────────────┘
Large List Success Checklist
✅ LARGE LIST SUCCESS CHECKLIST
Before starting:
▢ Clean list thoroughly (remove 6+ month unengaged)
▢ Segment by engagement level (4+ tiers)
▢ Set up parallel domain strategy
▢ Prepare tier-specific content
▢ Configure enhanced monitoring
During warming:
▢ Monitor engagement by segment daily
▢ Adjust volume based on performance
▢ Clean bounces and complaints immediately
▢ Document what works for each tier
▢ Maintain old domain as backup
Scaling up:
▢ Wait for consistent metrics (i.e no decline in open rate or engagement) before adding new segments
▢ Test different content types with smaller segments first
▢ Monitor ISP-specific performance (Gmail vs Outlook vs Yahoo)
▢ Plan content calendar for post-warming period
Step-by-Step Implementation Guide
✅ Pre-Warming Setup (Do This First)
1. Set up email authentication (Bento customers: we've already done this for you)
- SPF record: Specify authorized sending servers
- DKIM: Add digital signature to emails
- DMARC: Set policy for failed authentication
2. Configure your email infrastructure (Bento customers: we've already done this for you)
- Set up email sending service (ESP)
- Configure domain settings
- Test email delivery to personal accounts
3. Prepare your content (easy with Bento)
- Create engaging email templates
- Write compelling subject lines
- Set up automated sequences
4. Segment your lists (easy with Bento)
- Identify highly engaged contacts
- Separate new vs. existing subscribers
- Tag contacts by engagement level
✅ Week 1 Action Items
Monday (Day 1):
- Send emails to team members
- Send emails to personal contacts (people you do business with)
- Monitor delivery and engagement
Tuesday-Friday:
- Maintain 50-100 email daily volume
- Focus on contacts who will definitely engage (like people you do business with)
- Track open rates and replies
Weekend check-in:
- Review engagement metrics
- Identify any delivery issues
- Prepare Week 2 contact list
✅ Week 2-4 Scaling Process
Each Monday: Plan the week's volume increase Each Wednesday: Mid-week metric review Each Friday: Assess performance and adjust next week's plan
Key monitoring points:
- Delivery rates remaining above 95%
- Open rates staying within target ranges
- No significant spam complaint spikes
Best Practices for Domain Warming Success
1. Start with Your Most Engaged Contacts
Do this:
- Email team members who expect your messages
- Send to recent customers and active subscribers
- Contact people who've explicitly requested emails
Don't do this:
- Email old, inactive lists
- Send to purchased or rented lists
- Contact people who haven't heard from you in years
2. Create Genuinely Engaging Content
Winning content types:
- Personal updates from the founder
- Exclusive behind-the-scenes content
- Valuable tips and insights
- Product updates subscribers care about
Content to avoid:
- Generic promotional emails
- Heavy sales pitches during warming
- Clickbait subject lines
- All-caps or spammy language
3. Encourage Positive Engagement
Ask recipients to:
- Reply with feedback or questions
- Forward to interested colleagues
- Mark emails as important
- Add your address to their contacts
Example warming email:
Subject: Testing our new email system (reply appreciated!)
Hi [Name],
We're testing emails from our new domain and wanted to make sure
everything's working properly.
Could you do us a favor and hit reply to let us know this email
arrived safely? We'd also appreciate if you could add our new
address to your contacts.
Thanks for helping us get this right!
Best,
[Your name]
4. Monitor and Adjust Based on Data
Daily checks:
- Delivery rates (should stay above 95%)
- Open rates (track trends, not absolutes)
- Any bounce or complaint spikes
Weekly reviews:
- Overall engagement trends
- Domain reputation scores
- Inbox placement rates
Red flags to watch for:
- Sudden drop in open rates
- Increase in bounces or complaints
- Emails starting to land in spam
5. What to Do When Warming Goes Wrong
Sometimes, despite your best efforts, domain warming hits a snag. Here's how to recover:
🚨 WARNING SIGNS YOU NEED TO BACK OFF:
🔴 IMMEDIATE ACTION REQUIRED:
├─ Open rates drop below 10%
├─ Spam complaints above 0.1%
├─ Delivery rates below 90%
└─ Emails consistently landing in spam folders
🟡 CAUTION - SLOW DOWN:
├─ Open rates trending downward 3+ days
├─ Engagement dropping week over week
├─ Bounce rates increasing
└─ Manual spam folder checks showing poor placement
The recovery process:
🛠️ WARMING RECOVERY PROTOCOL:
Step 1: PAUSE (1-2 days)
├─ Stop all sends immediately
├─ Analyze what went wrong
├─ Review recent sends for issues
└─ Check authentication settings
Step 2: RESET (Week 1)
├─ Drop back to 10-20 emails per day
├─ Send ONLY to your most engaged contacts
├─ Use proven, engaging content
└─ Monitor metrics obsessively
Step 3: REBUILD (Weeks 2-4)
├─ Slowly increase volume only after consistent good metrics
├─ Stay extra conservative with volume growth
├─ Focus heavily on engagement quality
└─ Document what's working differently
Step 4: RESUME (Month 2+)
├─ Gradually return to normal warming schedule
├─ Maintain heightened monitoring
├─ Keep detailed records for future reference
└─ Consider consulting a deliverability expert
Key principle: When in doubt, go slower. It's always better to extend your warming timeline than to damage your reputation permanently.
Common Mistakes That Kill Domain Warming
❌ Mistake #1: Rushing the Timeline
The temptation: "I need to send my campaign this week!" Why it fails: ISPs notice volume spikes and flag suspicious behavior The fix: Stick to the 30-day timeline, plan campaigns accordingly, use your old domain for campaigns until you've warmed up.
❌ Mistake #2: Using Poor Quality Lists
The temptation: "I'll warm up with this old email list I have" Why it fails: Low engagement hurts reputation from day one The fix: Use only fresh, engaged, opted-in contacts. You want to put your best foot forward.
❌ Mistake #3: Ignoring Authentication
The temptation: "I'll set up SPF/DKIM later" Why it fails: Unauthenticated emails are immediately suspicious The fix: Complete authentication setup before sending anything. If you're a Bento customer, we've already done this for you.
❌ Mistake #4: Sending Only Promotional Content
The temptation: "Every email should drive sales" Why it fails: Promotional emails have lower engagement rates The fix: Mix valuable content with occasional promotions.
❌ Mistake #5: Not Monitoring Metrics
The temptation: "Set it and forget it" Why it fails: Problems compound if not caught early The fix: Daily metric checks, weekly strategy reviews.
Tools for Domain Warming Success
Free Monitoring Tools
Email authentication checkers:
- AboutMy.email - Comprehensive email analysis
Reputation monitoring:
- Google Postmaster Tools - Gmail-specific insights
- SenderScore - Email reputation monitoring
Why We Don't Recommend Warming Services
There are a lot of services out there that claim to be able to warm your domain in a few days. We don't recommend them for anyone.
The risks of automated warming:
- Artificial engagement - ISPs can detect and penalize fake interactions
- Shared IP pools - Many services use shared IPs that may have poor reputation
- False security - Creates a false sense of deliverability success
Better alternatives:
- Manual warming - Send real emails to engaged subscribers
- Natural growth - Let your volume increase organically with real engagement
- Focus on quality - Build genuine relationships instead of gaming the system
Anything that sounds too good to be true is probably too good to be true.
Email Service Provider Features
Most modern ESPs offer warming support:
- Gradual volume ramping - Automatic send limits through manual segmentation
- Reputation monitoring - Built-in dashboards to track complaints and bounces
Bento offers a little more:
- Batched sending - We batch your emails to ensure you're not sending too many emails at once allowing you to send broadcasts over hours, days, and even weeks
- Deliverability alerts - We monitor your reputation and alert you if there are any issues
- Unlimited support - We're here to help you warm your domain with your own team
- Easy authentication - We handle authentication for you so you can focus on sending emails
Monitoring Your Warming Progress
Key Metrics to Track
Daily monitoring:
- Delivery rate: Should stay above 95%
- Bounce rate: Should remain below 5%
- Spam complaints: Must stay under 0.1% during warming
Weekly analysis:
- Open rate trends: Watch for consistent patterns
- Engagement quality: Replies, forwards, "not spam" clicks
- Inbox placement: Primary inbox vs. promotions/spam
After Domain Warming: Maintaining Your Reputation
Domain warming doesn't end at day 30. Here's how to protect your investment:
Ongoing Best Practices
Monthly maintenance:
- Clean unengaged subscribers
- Monitor reputation metrics
- Update authentication records as needed
Quarterly reviews:
- Analyze engagement trends
- Assess sending volume needs
- Review content performance
Annual audits:
- Complete deliverability assessment
- Update domain warming processes
- Train team on best practices
When to Re-warm
You may need to restart warming if:
- Volume drops significantly for 3+ months
- Major reputation damage occurs
- Switching to new sending infrastructure
- Adding new types of email campaigns
FAQ: Your Domain Warming Questions Answered
Q: Can I speed up domain warming to 2 weeks?
A: While possible with perfect execution, 30 days is recommended for sustainable results. Rushing often leads to reputation damage that takes months to recover.
Q: Do subdomains need separate warming?
A: Yes, each subdomain (like newsletter.company.com) needs its own warming process, though it may be shorter than the main domain.
Q: What if my warming metrics are poor?
A: Pause and assess. Poor early metrics often indicate list quality issues or content problems. Fix the root cause before continuing.
Q: Can I send promotional emails during warming?
A: Sparingly. Focus 80% on relationship-building content, 20% on soft promotions. Save aggressive sales campaigns for after warming.
Q: How do I warm multiple domains simultaneously?
A: Use separate warming schedules for each domain. Don't cross-contaminate lists between domains during warming.
Q: Does domain age affect warming time?
A: Older domains with no email history still need full warming. Previous email activity (if positive) can slightly accelerate the process.
Q: What if I followed all the steps but I'm still landing in spam?
A: This usually means the spam filter learned you're not sending mail people actually want. Domain warming only works for legitimate senders—you can't warm your way out of poor content or unwanted emails.
Q: Should I follow different rules for Gmail specifically?
A: From a domain perspective, not an IP perspective, we tend to treat all ISPs similarly but we do know that Gmail tends to prefer not sending all emails at once and instead sending them slowly in batches. Practically, this means for configuring your broadcasts to send over hours not all at once.
Quick Start Checklist
Ready to begin domain warming? Use this checklist:
Week Before Starting:
- [ ] Set up SPF, DKIM, and DMARC records
- [ ] Configure email sending platform
- [ ] Segment contact lists by engagement level
- [ ] Prepare Week 1 content and templates
- [ ] Set up monitoring tools
Day 1:
- [ ] Send first 50 emails to highly engaged contacts
- [ ] Monitor delivery rates
- [ ] Track initial engagement metrics
- [ ] Document any issues
Ongoing:
- [ ] Increase volume according to schedule
- [ ] Monitor metrics daily
- [ ] Adjust strategy based on performance
- [ ] Maintain detailed records
The Bottom Line
Domain warming isn't glamorous, but it's the foundation of reliable email delivery. Those 30 days of careful volume building can mean the difference between emails that reach customers and emails that disappear into digital black holes.
Remember the core principles:
- Start small with highly engaged contacts
- Increase gradually over 30 days
- Monitor closely and adjust when needed
- Focus on engagement over volume
If you take away just one thing: Domain warming is an investment in your email program's future. Skip it, and you'll spend months recovering. Do it right, and you'll have a reliable foundation for all your email marketing.
Need help with domain warming? Most email service providers offer guidance and support. Don't wait until you've damaged your reputation to ask for help.
BONUS: Gmail's Special Requirements (Yes, They're Different)
Gmail is the 800-pound gorilla of email providers, and they have some specific requirements that differ from the general 30-day approach:
📧 GMAIL'S WARMUP RULES
╭─────────────────────────────────────────────╮
│ Start: 10-20 emails every few HOURS │
│ (Not 50-100 per DAY like other ESPs) │
│ │
│ Timeline: 4-6 weeks minimum │
│ (Not 30 days like others) │
│ │
│ Rule: EVERY domain + IP combo needs warmup│
│ (Even if one component is already warm) │
╰─────────────────────────────────────────────╯
The Gmail 10-20 Rule
When Gmail says "start small," they mean it. Their recommendation:
- 10-20 emails every few hours (not per day)
- You can send multiple batches per day, just keep each batch tiny
- Never try to send even 100 emails on your first send—it'll land in spam
🕐 GMAIL HOURLY SCHEDULE EXAMPLE:
9 AM: 📧📧📧 (15 emails to team)
12 PM: 📧📧📧 (18 emails to customers)
3 PM: 📧📧📧 (12 emails to partners)
6 PM: 📧📧📧 (20 emails to engaged users)
Daily total: ~65 emails across 4 small batches
Bento's batching feature is designed to help you follow this rule.
Why Gmail is Different
Gmail's spam filtering is fundamentally different from other providers:
🔍 GMAIL VS. EVERYONE ELSE:
Other ESPs: 🛡️ Start with IP reputation filters
📧 Then add content filtering on top
Gmail: 📧 Start with content filtering as base
🛡️ Add IP reputation as extra layer
What this means for you:
- Gmail cares more about WHO you email than WHERE you email from
- Content quality matters more than IP reputation
- Engagement signals are absolutely critical
The Harsh Truth About Domain + IP Combinations
Here's something that trips up a lot of people:
⚠️ EVERY COMBINATION NEEDS WARMING:
✅ Warm domain + Warm IP = Ready to send
❌ Warm domain + NEW IP = Needs warming
❌ NEW domain + Warm IP = Needs warming
❌ NEW domain + NEW IP = Needs warming
Real example: You've been sending from [email protected] successfully for months. You get a dedicated IP and think you're good to go. Wrong! Gmail sees this as a new domain + IP combination and you're back to square one.
Don't Mix Your Audiences Too Early
Here's a mistake we see all the time during Gmail warmup:
❌ MIXING MISTAKE:
Day 1: Send to engaged customers (great!)
Day 2: Mix in some cold prospects (disaster!)
Result: Gmail flags the mixed signals
✅ CLEAN SEGMENTATION:
Week 1-2: Only hyper-engaged contacts
Week 3-4: Gradually add less engaged segments
Week 5+: Full audience deployment
Why this matters: Gmail's algorithms are looking for consistent patterns. Mixed signals confuse the system and can tank your reputation.
The Real Truth: Domain Warming Is Actually a Conversation
Here's something most guides won't tell you—domain warming isn't just about gradually increasing volume. It's actually a complex conversation between you and the spam filtering systems at Gmail, Yahoo, Outlook, and others.
Think of it this way:
🤖 SPAM FILTER'S INTERNAL MONOLOGUE:
Week 1: "New domain... sending small volumes...
content looks reasonable... users seem engaged...
I'll deliver to inbox but keep watching..."
Week 2: "Still consistent patterns... good engagement...
no spam complaints... okay, they seem legit..."
Week 3: "Volume increasing but engagement holding steady...
users aren't marking as spam... this looks good..."
Week 4: "Established pattern of good behavior.
I trust this sender. Let's continue to deliver to inbox!"
The Spam Filter Is Smarter Than You Think
Modern spam filters aren't just checking boxes—they're complex machine learning systems that are constantly learning. They're:
🧠 WHAT SPAM FILTERS ARE ACTUALLY DOING:
✅ Sampling your content for quality signals
✅ Tracking how users interact with your emails
✅ Comparing your patterns to known spammer behavior
✅ Building a personality profile of your mail stream
✅ Testing your emails in different folders to see user response
✅ Cross-referencing your domain with other reputation signals
The key insight: The filter isn't just measuring your volume ramp—it's learning who you are as a sender.
Why Bad Senders Fail Even With Perfect Warming
Here's the harsh reality: You can follow every single step in this guide perfectly, and still fail if you're not genuinely sending mail people want.
🎭 THE TRAP:
Bad Sender: "I did everything right! I started small, ramped slowly,
followed the timeline... but I'm still in spam!"
Reality: You followed the FORM of warming perfectly, but the
spam filter learned you send unwanted mail.
Result: 🗑️ Spam folder, despite "perfect" execution
Examples of senders this happens to:
- Cold email outreach companies
- Purchased email list users
- "Growth hackers" sending unsolicited pitches
- Anyone sending mail people don't actually want
- People with a lot of automated bots on their list (waitlists run into this a lot)
The bottom line: Domain warming amplifies what you already are. If you're a good sender, it helps you. If you're a bad sender, it just teaches the filter to block you more effectively.
The Three Pillars of Successful Domain Warming
For domain warming to actually work, you need all three:
🏛️ THE THREE PILLARS:
Pillar 1: TECHNICAL EXECUTION
├─ Proper volume ramping
├─ Good authentication (SPF/DKIM/DMARC)
├─ Clean sending infrastructure
└─ Following timelines
Pillar 2: AUDIENCE QUALITY
├─ Opted-in subscribers only
├─ Recent, engaged contacts
├─ People who actually want your emails
└─ Clean, validated email addresses
Pillar 3: CONTENT VALUE
├─ Emails people genuinely want to receive
├─ Content that generates positive engagement
├─ Clear value proposition
└─ Authentic, non-spammy messaging
If any pillar is weak, domain warming fails. You can't warm your way out of bad content or poor list quality.
How to Know If Your Warming Will Actually Work
Ask yourself these honest questions before starting:
🔍 THE WARMING REALITY CHECK:
❓ "If this email landed in MY spam folder, would I:
a) Move it to inbox because I want it? ✅
b) Leave it in spam because it's not relevant? ❌"
❓ "Did the people I'm emailing actually ASK for this content?"
a) Yes, they specifically opted in ✅
b) Well, I think they'd be interested... ❌
❓ "When I send these emails, do people typically:
a) Open, read, and sometimes reply? ✅
b) Ignore or complain about them? ❌"
If you answered mostly B's: Domain warming won't save you. Fix your content and audience first, then warm.
If you answered mostly A's: You're a good sender! Domain warming will work beautifully for you.