What's Happening?
Google has recently implemented stricter spam filtering policies that are affecting cold email deliverability across the industry. While Mailscale handles all your technical infrastructure (DNS, domains, IP reputation, warm-up), there are critical copywriting and sending practices you need to follow to maintain high inbox rates.
Good news: The technical infrastructure is not the issue—Mailscale has you covered there. The key to success now lies in how you're writing and sending your emails.
Google's New Focus: Engagement-Based Filtering
Google is now penalizing emails based on lack of engagement, not just spam complaints. This means:
- ❌ Old way: You only went to spam if people marked you as spam
- ✅ New way: You'll be filtered to spam if recipients consistently ignore your emails with zero engagement
Bottom line: If you're getting 0% reply rates, your emails will eventually be marked as spam automatically, even without manual spam reports.
Critical Best Practices (Your Action Items)
1. Write Conversational Copy
- Avoid sales-heavy or marketing language, even without spam words
- Write emails you'd send to a friend on WhatsApp
- Focus on starting conversations, not making pitches
- Keep it short and natural
❌ Too sales-y: "I wanted to reach out to introduce our cutting-edge solution that helps businesses optimize their workflow and increase productivity by 40%."
✅ Conversational: "Hey [Name], noticed you're using [tool]. We just wrapped up testing with 50 companies in your space—found something that might be relevant. Worth a quick chat?"
❌ Too formal: "I am writing to inquire whether your organization would be interested in exploring a partnership opportunity."
✅ Conversational: "Quick question—are you guys still handling [process] manually, or have you automated that by now?"
2. Shorten Your Sequences
- Recommended: 3 steps maximum (previously 4-5 was common)
- If someone ignores 3 emails, additional follow-ups hurt more than help
- Each ignored email damages your sender reputation
3. Write Specific, Meaningful Subject Lines
- Avoid vague subject lines that don't provide context
- Make subject lines relevant and clear about the email's purpose
- Generic subjects hurt engagement rates
❌ Vague subjects that underperform:
- "Quick question"
- "Following up"
- "Touching base"
- "Checking in"
- "Re: your company"
✅ Specific, meaningful subjects:
- "[Company name] - [specific tool/process] question"
- "Saw your post about [specific topic]"
- "[Industry] study - relevant to [their company]"
- "[Mutual connection] suggested I reach out"
- "Alternative to [tool they're using]"
The more specific and relevant your subject line, the higher your open and engagement rates will be.
3. Maximize Email Variability
- Don't just use basic spin syntax with the same phrases
- Consider unique variations for each email when possible
- Avoid repeating the same long phrases across campaigns
- If specific phrases get flagged, they could blacklist that entire copy block
❌ Bad spin syntax (same phrases repeated):
Hi {FirstName|Hey FirstName},
{We help companies|We assist businesses|We support organizations} {increase revenue|boost sales|grow income}.
{Would you be interested|Are you interested|Interested} in learning more?
✅ Better approach (truly different variations):
Version 1: "Hey [Name], quick question about your [process]..."
Version 2: "[Name] - saw you're using [tool]. Curious if..."
Version 3: "Hi [Name], did a study on [industry]. Found something relevant..."
4. Optimize Your Warm-Up Settings
- Set your warm-up reply rate to 50-80% (not the standard 30%)
- This signals to Google that your mailbox consistently gets high engagement
- Mailscale handles the warm-up infrastructure—just adjust this setting in your cold email tool
Action item: In your cold email platform (Instantly, Smartlead, etc.), go to warm-up settings and increase the reply rate to 80-90%. This dramatically improves how email providers view your sender reputation.
5. Give New Mailboxes Time
- The first 3 months are critical for new Google mailboxes
- They're most vulnerable during this period (like building immunity)
- After 3 months of good engagement, mailboxes become significantly more stable
- Consider: Extending warm-up period from 2-3 weeks to 4-6 weeks for new accounts
Important: Longer warm-up periods directly improve deliverability. If you're experiencing issues, try warming up for an additional 2-4 weeks before sending cold campaigns. This extra time helps build stronger sender reputation with Google.
6. Remove Unnecessary Elements
- Don't include unsubscribe links (not needed for pure cold email)
- Avoid tracking opens/clicks if not essential
- Keep emails as simple and natural as possible
7. Test Your Copy First
- Run placement tests with two versions:
1. Your actual campaign copy
2. A simple, conversational test message
- If the conversational test inboxes but your copy doesn't, the issue is your copy, not the infrastructure
- One phrase in your email could be triggering spam filters
Testing example:
- Test 1 (Your campaign): If this lands in spam...
- Test 2 (Simple message): "Hey, I'm going to be in Miami next week. Can we grab lunch?"
- If Test 2 inboxes fine, your infrastructure works—you need to adjust your copy
8. Filter by Email Provider
- If you're inboxing 100% to Microsoft but only 50% to Google, temporarily pause Google recipients
- Focus sends only on providers where you're inboxing well
- Save Google contacts for when deliverability improves
- This protects your sender reputation and maximizes reply rates
Pro tip: While you pause Google contacts, continue warming up those mailboxes with extended warm-up periods. The longer your mailboxes warm up (4-6 weeks instead of 2-3), the better they'll perform when you resume sending to Google. Think of it as building a stronger foundation before launching campaigns.
What About High-Volume Senders?
If you're achieving 10-15%+ reply rates, there's evidence you may be able to:
- Increase sending volume from 30 to 40-50 emails per mailbox per day
- High engagement signals to Google you're a trusted sender
- Test with 2-3 mailboxes first before scaling
Remember: Mailscale Has Your Back on Infrastructure
We're handling:
- ✅ Premium IP addresses and sender reputation
- ✅ Proper DNS record configuration
- ✅ Domain and mailbox setup
- ✅ Technical warm-up infrastructure
- ✅ SMTP delivery optimization
Your focus should be on:
- ✍️ Writing engaging, conversational copy
- 📊 Monitoring engagement metrics
- 🎯 Testing and optimizing your messaging
- 📧 Following the sequence and sending best practices above
Follow-Up Sequence Examples
❌ Too aggressive (5+ follow-ups):
- Day 1: Initial pitch
- Day 3: "Just following up..."
- Day 5: "Wanted to bump this up..."
- Day 7: "Circling back..."
- Day 10: "Last attempt..."
✅ Better approach (3 steps max):
- Email 1: "Hey [Name], noticed you're handling [process] with [tool]. We just tested something with 20 companies in your space—cut time by half. Worth exploring?"
- Email 2 (3 days later): "[Name] - did you get a chance to look at this? Happy to show you the breakdown if it's relevant."
- Email 3 (4 days later): "No worries if timing's not right. If you want to revisit this in Q1, just let me know."
Need Help?
If you're experiencing deliverability issues:
1. Run placement tests with your current copy
2. Test with ultra-conversational copy
3. Review your engagement rates
4. Reach out to our support team—we can help troubleshoot
Remember: This isn't an infrastructure problem—Mailscale has that covered. Success now depends on writing better copy and following engagement best practices.
Questions? Contact our support team for assistance.