Deliverability is binary. Either your emails hit the inbox or they hit spam. There's no middle ground.
Here's the 15-point audit that catches 95% of deliverability issues.
The Checklist
1. SPF Record Authentication
Check: Does your SPF record include your sending provider?
Go to MXToolbox.com:
- Enter your domain
- Click "SPF Record"
- Look for your email provider in the record
What you need:
- If using Google Workspace:
include:_spf.google.com - If using Instantly:
include:sendingservice.net(or equivalent) - Record should exist and be valid
Red flag: SPF record missing or incomplete. Add it immediately.
Fix: Contact your DNS provider, add SPF record, wait 24 hours for propagation.
2. DKIM Authentication
Check: Is DKIM configured?
Google Postmaster Tools > Authentication:
- DKIM status should be GREEN
- If DKIM is GRAY or RED, it's failing
What you need:
- DKIM record published on your domain
- DKIM key pair generated by your email provider
- Both should match
Red flag: DKIM failing. This kills deliverability.
Fix: Generate DKIM keys in your email host, publish to DNS, verify in Postmaster.
3. DMARC Policy
Check: Does your domain have DMARC policy?
Google Postmaster Tools > Authentication:
- DMARC status should show "Policy present"
- Policy should be
p=quarantineorp=reject(notp=none)
What you need:
- DMARC record:
v=DMARC1; p=quarantine; rua=mailto:[your email] - Monitors domain reputation
- Tells mailboxes to distrust spoofed emails
Red flag: No DMARC policy. Add one immediately.
Fix: Add DMARC record to DNS. Use p=quarantine (strict but allows monitoring).
4. Warmup Completion
Check: Has this inbox completed 14-day warmup?
Instantly > Inbox Settings:
- View warmup status (should show "Completed" or "Active")
- If "In Progress," don't send campaigns yet
What you need:
- All inboxes should be warmup-complete before production
- No exceptions
Red flag: Running campaigns before warmup complete. This is #1 mistake.
Fix: Wait 14 days. Yes, it's slow. Yes, it's necessary.
5. Bounce Rate
Check: What's your bounce rate?
Instantly > Campaign Analytics:
- Select campaign
- Look for "Bounce Rate"
- Should be <3%
What you need:
- <3% bounce rate is safe
- 3-5% bounce rate is concerning
- >5% bounce rate is broken (list quality issue)
Red flag: >5% bounce rate. Your list has bad email addresses.
Fix: Check list quality. Use Hunter or RocketReach to verify emails. Remove invalid addresses.
6. Spam Complaint Rate
Check: How many people mark your emails as spam?
Instantly > Campaign Analytics:
- Look for "Spam Complaint Rate" or "Mark as Spam %"
- Should be <0.3%
What you need:
- <0.3% is safe
- 0.3-0.5% is concerning
- >0.5% is broken (copy or list issue)
Red flag: >0.5% spam complaints. Either your copy is too salesy or your list sucks.
Fix: Tone down copy, remove unengaged segments, rebuild list from scratch.
7. Inbox Placement (Google Postmaster)
Check: What % of emails hit the inbox vs spam?
Google Postmaster Tools (postmaster.google.com):
- Domain dashboard
- Click "Inbox Placement"
- Should show 90%+ inbox, <10% spam
What you need:
- 90%+ inbox placement is safe
- 80-90% is concerning
- <80% is broken
Red flag: <80% inbox placement. Something is very wrong.
Fix: Check SPF/DKIM/DMARC (items 1-3). Check bounce rate (item 5). Check spam complaints (item 6).
8. Inbox Placement (by domain reputation)
Check: What does Postmaster say about your domain reputation?
Google Postmaster Tools:
- Domain dashboard
- Look for "Domain Reputation" card
- Should say "Not in a bad reputation" or "Good reputation"
What you need:
- "Good" or "Not in a bad reputation" = safe
- "Bad reputation" = PAUSE EVERYTHING
Red flag: "Bad reputation" flagged. Your domain is burned.
Fix: Stop sending. Wait 30 days. If sending pattern was bad, start over with new domain.
9. Authentication Status
Check: SPF, DKIM, DMARC all green?
Google Postmaster Tools:
- Domain dashboard
- "Authentication" tab
- Should show GREEN for all three
What you need:
- All three should be green
- No exceptions
Red flag: Any RED or GRAY status. Fix immediately.
Fix: Review items 1-3 above.
10. Daily Send Limits
Check: Are you exceeding your daily inbox limit?
Instantly > Inbox Settings:
- View each inbox's daily limit
- Check actual sends vs limit
- Should never exceed by more than 5%
What you need:
- Respect your daily limits exactly
- If limit is 100, don't send 110
Red flag: Exceeding limits regularly. Gmail notices.
Fix: Lower your daily limit. Be conservative.
11. Pool Rotation Configuration
Check: Are you using multiple inboxes (pool)?
Instantly > Pools:
- If sending >500/day, you should have multiple inboxes
- All inboxes should be in one pool
- Rotation should be Round Robin or Random
What you need:
- 50+ inboxes for 5,000/day sending
- Distributed evenly
- Proper rotation configured
Red flag: All sends from one inbox at scale. Domain will burn out in 2 weeks.
Fix: Create pool with 50+ inboxes. Ramp gradually.
12. CNAME Tracking Domain
Check: Is your tracking domain authenticated?
Instantly > Settings > Tracking Domains:
- Should show your CNAME record
- Status should be "Active" or "Verified"
What you need:
- Tracking domain should be subdomain of your sending domain
- Example:
click.yourdomain.com - CNAME properly configured
Red flag: Unverified tracking domain. Postmaster can't verify your authenticity.
Fix: Add CNAME record for tracking domain. Verify in Instantly.
13. Reply Automation Status
Check: Is reply handling enabled?
Instantly > Campaign Settings:
- "Reply Handling" should be enabled
- Replies should auto-tag/folder
- AI replies (if enabled) should be working
What you need:
- At minimum: Auto-folder replies so they don't stay in main inbox
- Ideal: AI reply handling to maintain engagement
Red flag: Replies staying in main inbox. Gmail sees engagement as low.
Fix: Enable reply automation. Keep main inbox clean. Replies should move to folder.
14. Recipient Engagement
Check: Are recipients actually engaging with your emails?
Google Postmaster Tools:
- "User Engagement" card
- Should show "Good" or "High"
- Shows % of recipients opening, clicking
What you need:
- >20% open rate from warmup recipients = good engagement signal
- >5% click rate = good engagement signal
Red flag: <10% open rate. Recipients aren't engaging; Gmail sees this.
Fix: Check warmup list quality. Are you sending to people who'll actually reply? If not, your warmup list is bad.
15. Recipient List Quality Verification
Check: Are your email addresses actually valid?
Hunter.io or RocketReach:
- Batch upload 100-1,000 addresses
- Get verification report
- Should show 90%+ valid
What you need:
- <5% invalid email rate
- No role accounts (info@, support@, hello@)
- Real people with personalized inboxes
Red flag: >5% invalid emails. List quality is poor.
Fix: Use Apollo or Clay to source list. Always verify with Hunter before uploading to Instantly.
Quick Audit Workflow
Run this checklist monthly:
Weekly (5 min):
- Check Instantly bounce rate (item 5)
- Check Instantly spam complaints (item 6)
- Monitor daily send limits (item 10)
Monthly (30 min):
- Run Google Postmaster audit (items 7-9, 14)
- Check pool configuration (item 11)
- Verify CNAME tracking (item 12)
- Verify reply automation (item 13)
Quarterly (1 hour):
- Run full 15-point checklist above
- Batch verify 100-500 email addresses (item 15)
- Review and fix any red flags
Red Flags Require Immediate Action
If you find ANY of these, pause campaigns immediately:
- SPF/DKIM/DMARC authentication failing (items 1-3)
- Warmup incomplete (item 4)
- Bounce rate >5% (item 5)
- Spam complaints >0.5% (item 6)
- Inbox placement <80% (item 7)
- Domain reputation "Bad" (item 8)
- No CNAME verification (item 12)
- Invalid emails >10% (item 15)
These indicate structural problems that will destroy your domain.
When to Retire a Domain
If after this audit you find:
- Inbox placement <60%
- Domain reputation "Bad"
- Bounce rate >10%
- Spam complaints >1%
Retire the domain. Don't try to recover it. Start with new domain.