After building 500+ cold email systems, I've learned that success isn't about the perfect email copy or the fanciest automation tool. It's about having rock-solid infrastructure that ensures your emails actually reach the inbox.
Most people jump straight into sending campaigns without proper setup, then wonder why their emails land in spam or their domains get blacklisted. This guide will show you exactly how to build professional cold email infrastructure that delivers results.
What You'll Learn: The exact step-by-step process to set up cold email infrastructure that achieves 95%+ inbox placement rates, based on real implementations across hundreds of successful campaigns.
Part 1: Domain Strategy & Selection
Your domain strategy is the foundation of successful cold email. Get this wrong, and nothing else matters.
How Many Domains Do You Need?
Here's the formula we use:
Domain Selection Best Practices
- Never use your main domain - Always use separate domains for cold outreach
- Choose similar variations - getleadmark.io, tryleadmark.io, leadmarkapp.io
- Avoid hyphens and numbers - They look spammy and hurt deliverability
- Prefer .com, .io, .co - Avoid exotic extensions like .biz or .info
- Check domain history - Use tools like DomainTools to verify clean history
| Domain Type | Example | Recommended? | Why |
|---|---|---|---|
| Main Domain | leadmark.io | ❌ Never | Risk to primary business |
| Variation | getleadmark.io | ✅ Yes | Similar but separate |
| Redirect | leadmark.co | ✅ Yes | Redirects to main site |
| Hyphenated | lead-mark.io | ❌ No | Looks spammy |
Where to Buy Domains
We recommend these registrars based on price and ease of management:
- Porkbun - Best prices, clean interface ($8-10/year for .com)
- Namecheap - Good bulk management tools ($9-12/year)
- GoDaddy - Avoid if possible (overpriced, aggressive upselling)
⚠️ Important: Always enable domain privacy/WHOIS protection to prevent your personal information from being publicly visible.
Part 2: Email Account Setup
Once you have domains, you need to create professional email accounts. Here's the breakdown:
Google Workspace vs Microsoft 365
| Feature | Google Workspace | Microsoft 365 |
|---|---|---|
| Price | $6/user/month | $6/user/month |
| Setup Difficulty | Easy (30 mins) | Moderate (1 hour) |
| Deliverability | Excellent | Good |
| Integration | Better with tools | Limited options |
| Reputation | Stronger for cold email | Better for corporate |
Our Recommendation: Google Workspace for 90% of cold email use cases.
How Many Email Accounts Per Domain?
- Safe limit: 3-5 accounts per domain
- Maximum: 7 accounts (pushing it)
- Naming convention: firstname@, firstname.lastname@, f.lastname@
✅ Pro Tip: Use real-sounding names, not generic accounts like info@ or sales@. Personal names get 23% better open rates.
Part 3: DNS & Authentication Configuration
This is where most people mess up. Proper DNS configuration is non-negotiable for inbox placement.
SPF (Sender Policy Framework)
SPF tells receiving servers which IP addresses are authorized to send email from your domain.
DKIM (DomainKeys Identified Mail)
DKIM adds a digital signature to your emails, proving they haven't been tampered with.
- Generated automatically by Google Workspace
- Must be added to DNS as a TXT record
- Usually looks like: google._domainkey
DMARC (Domain-based Message Authentication)
DMARC tells receiving servers what to do with emails that fail SPF or DKIM checks.
Additional DNS Records
- MX Records: Point to Google's mail servers
- A Record: Point domain to a simple landing page
- CNAME: For subdomain redirects if needed
🔍 Testing Your Setup: Use MXToolbox.com to verify all DNS records are properly configured. Green checkmarks across the board before sending any emails!
Part 4: Email Warming Protocol
Email warming is like going to the gym - you can't lift heavy weights on day one. Here's our proven 30-day warming protocol:
Week 1-2: Foundation Phase
- Day 1-3: 2-5 emails per day
- Day 4-7: 5-10 emails per day
- Day 8-14: 10-20 emails per day
- Focus: Reply to emails, not just sending
Week 3-4: Scaling Phase
- Day 15-21: 20-30 emails per day
- Day 22-30: 30-40 emails per day
- Start introducing cold outreach (20% of volume)
Week 5+: Production Phase
- Maintain 40-50 emails per day maximum
- 50% warming, 50% cold outreach
- Monitor metrics constantly
⚠️ Never Skip Warming: Sending cold emails without proper warming is the fastest way to destroy your domain reputation. Be patient - it's worth it.
Part 5: Platform Configuration (Instantly vs Smartlead)
Both platforms work well, but here's how to set them up properly:
Instantly Setup
- Connect accounts via SMTP/IMAP (not OAuth)
- Set sending limits: 30-40 emails/day/account
- Configure warmup: Enable automatic warming
- Set delays: 60-180 seconds between emails
- Enable tracking: But limit to 30% of emails
Smartlead Setup
- Use app passwords for Google Workspace
- Enable "Warm Up" feature for all accounts
- Set daily limits: Start at 20, scale to 40
- Configure ESP matching: Critical for deliverability
- Use subsequences: Not single long sequences
| Setting | Instantly | Smartlead |
|---|---|---|
| Daily Limit | 30-40 emails | 30-40 emails |
| Delay Between | 60-180 seconds | 90-240 seconds |
| Warmup % | 30-50% | 40-60% |
| Tracking | 30% max | 25% max |
Part 6: Monitoring & Maintenance
Set it and forget it doesn't work with cold email. Here's what to monitor:
Daily Checks (5 minutes)
- Bounce rate (should be under 3%)
- Open rate (target 40-60%)
- Reply rate (aim for 5-10%)
- Spam complaints (must be under 0.1%)
Weekly Checks (30 minutes)
- Domain reputation (Google Postmaster Tools)
- Blacklist status (MXToolbox)
- Email placement tests (GlockApps)
- Authentication status (DMARC reports)
Red Flags to Watch For
- 🚨 Open rate drops below 30%
- 🚨 Bounce rate exceeds 5%
- 🚨 Sudden increase in spam complaints
- 🚨 Domains appearing on blacklists
- 🚨 Email provider warnings
Part 7: Real Cost Breakdown
Let's talk real numbers for a professional setup:
| Item | Cost | Quantity | Monthly Total |
|---|---|---|---|
| Domains | $10/year | 10 domains | $8.33 |
| Google Workspace | $6/user | 30 accounts | $180 |
| Instantly/Smartlead | $97/month | 1 account | $97 |
| Warming Service | $15/account | 30 accounts | $450 |
| Total | $735.33 |
ROI Calculation: If you close just one $5,000 deal per month, that's a 580% ROI. Most of our clients close 3-5 deals minimum.
Want Us to Build Your Infrastructure?
Skip the learning curve. Get professional cold email infrastructure built by experts who've done it 500+ times.
Get Your Infrastructure Built →Frequently Asked Questions
Q: Can I use free email accounts like Gmail?
No. Free accounts have strict sending limits and poor deliverability for cold email. Professional infrastructure requires Google Workspace or Microsoft 365.
Q: How long before I can send at full volume?
With proper warming, you can reach full volume (40-50 emails/day/account) in 30 days. Rushing this process will damage your deliverability.
Q: Should I use tracking pixels?
Sparingly. Tracking pixels can hurt deliverability. We recommend tracking only 25-30% of your emails and relying on reply rates as your primary metric.
Q: What if my domain gets blacklisted?
First, stop all sending immediately. Then identify the cause (usually sending too fast or poor list quality). Submit delisting requests and implement stricter quality controls. This is why we use multiple domains - redundancy is key.
Q: Is it worth doing this myself vs hiring an agency?
If you have the technical skills and time, DIY can work. However, most businesses find that the opportunity cost of learning and implementing everything correctly exceeds the cost of professional setup. One mistake can blacklist your domains and waste months of time.
🎯 Key Takeaway: Cold email infrastructure isn't complicated, but it requires attention to detail and patience. Follow this guide step-by-step, don't cut corners, and you'll have a system that generates leads consistently for years.