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Cold Email Domain Setup Checklist: 15 Steps (2026)
By Saksham JainPublished on: Mar 31, 2026 · 10 min read · Last reviewed: Mar 2026
TL;DR
Every step from buying a domain to sending your first campaign. Based on 10,000+ domain setups on InboxKit.
The Complete 15-Step Checklist
Based on 10,000+ domain setups on InboxKit.
| Step | Task | Time | InboxKit Automated? | Common Mistake |
|---|---|---|---|---|
| 1 | Choose domain name | 5 min | Search tool | Using exact brand names |
| 2 | Select extension (.com/.co) | 2 min | TLD filter | Choosing .xyz (low trust) |
| 3 | Purchase domain | 2 min | In-app | Overpaying at registrars |
| 4 | Point nameservers | 5 min | Automatic | Wrong NS, 48h propagation |
| 5 | Configure SPF | 3 min | Automatic | >10 DNS lookups (RFC 7208) |
| 6 | Configure DKIM | 3 min | Automatic | Wrong selector, weak key |
| 7 | Configure DMARC | 2 min | Automatic | Starting with p=reject |
| 8 | Set up MX records | 2 min | Automatic | Missing MX = no replies |
| 9 | Create mailboxes (3/domain) | 5 min | Automatic | >5 per domain (risky) |
| 10 | Set profile pictures | 3 min | Bulk upload | Skipping (hurts trust) |
| 11 | Configure MFA | 2 min | Automatic | Skipping (Google flags) |
| 12 | Start warmup | 1 min | $3/mailbox/mo | Skipping warmup entirely |
| 13 | Connect sequencer | 3 min | One-click export | Wrong SMTP settings |
| 14 | Set up domain forwarding | 2 min | Dashboard | No website on domain |
| 15 | Enable monitoring | 1 min | InfraGuard | No monitoring = blind |
| Total | ~40 min manual | ~10 min InboxKit |
Source: InboxKit Quick Setup wizard automates steps 4-12. DNS record formats per Google Workspace Admin Help (support.google.com/a/answer/33786).
Domain Extension Impact on Deliverability
Extension choice matters more than most people think.
| Extension | Inbox Rate | Cost/Year | Recommendation | Source |
|---|---|---|---|---|
| .com | 85-95% | $12-15 | Best if available | InboxKit IPT data |
| .co | 82-92% | $8-10 | Great alternative | InboxKit IPT data |
| .io | 80-90% | $30-40 | Good for tech | InboxKit IPT data |
| .net | 78-88% | $12-15 | Acceptable | Industry data |
| .xyz | 60-75% | $1-3 | Avoid | Validity 2025 |
| .info | 55-70% | $2-5 | Avoid | Validity 2025 |
Why .xyz and .info perform poorly: These extensions are heavily used by spammers due to low cost. ISPs have learned to be suspicious of them. Source: Validity 2025 Deliverability Report.
Mailbox Density: How Many Per Domain
The number of mailboxes per domain affects deliverability risk.
| Mailboxes/Domain | Risk | Volume/Day | Best For |
|---|---|---|---|
| 1-2 | Very Low | 30-60 | Conservative |
| 3 | Low | 90 | Recommended |
| 4-5 | Medium | 120-150 | With monitoring |
| 6-10 | High | 180-300 | Agencies only |
| 10+ | Very High | 300+ | Not recommended |
Why 3 is the sweet spot: 3 mailboxes x 30 emails/day = 90/day per domain. At $2.99/mailbox: $8.97/mo per domain. Cost-effective without reputation risk.
Source: InboxKit recommended setup, aligned with Instantly and SmartLead best practices.
Warmup Timeline
Don't skip warmup. The data is clear.
| Day | Volume/Mailbox | Inbox Placement | Activity |
|---|---|---|---|
| 1-3 | 5/day | 40-60% | Warmup only |
| 4-7 | 10-15/day | 55-70% | Warmup + light testing |
| 8-14 | 15-25/day | 70-85% | Small campaigns OK |
| 15-21 | 25-40/day | 80-90% | Ramp campaigns |
| 22-30 | 30-50/day | 85-95% | Full volume |
InboxKit warmup: $3/mailbox/month, isolated pools (not shared). Source: InboxKit warmup data across 5,000+ cycles.
Total Cost Calculator
What it actually costs to set up cold email infrastructure.
| Scale | Domains | Mailboxes | Domain Cost | Mailbox Cost | Warmup | Total/Month |
|---|---|---|---|---|---|---|
| Starter | 4 | 12 | $4/mo | $35.88 | $36 | $75.88 |
| Growth | 12 | 36 | $12/mo | $107.64 | $108 | $227.64 |
| Scale | 28 | 84 | $28/mo | $251.16 | $252 | $531.16 |
| Agency | 56 | 168 | $56/mo | $502.32 | $504 | $1,062.32 |
Math: Domain ~$12/year = $1/mo. Google Workspace $2.99/mailbox/mo. Warmup $3/mailbox/mo.
Source: InboxKit pricing (inboxkit.com). No platform fees, no minimums.
Frequently Asked Questions
10 minutes with InboxKit (automated DNS), then 14 days warmup before first campaign. Manual setup: 40-60 minutes + same warmup.
About 12 domains with 3 mailboxes each (36 mailboxes x 30/day = 1,080/day). Cost: ~$228/mo on InboxKit.
You can but inbox placement drops from 85-95% to 15-35%. The 14-day warmup is the difference between campaigns that work and campaigns in spam.
Both work. Use 70% Google + 30% Microsoft for provider diversity. InboxKit plans start at $39/mo and support Google, Microsoft, and Azure. Google warms up faster; Microsoft has higher daily limits.
4 domains, 12 Google mailboxes: $35.88/mo for mailboxes + $36/mo for warmup ($3/mailbox/mo add-on) = $75.88/mo total with warmup. Sends ~360 emails/day safely.
Sources & References
- 1
Google Workspace Admin Help(2026)
- 2
RFC 7208 SPF(2026)
- 3
- 4
- 5
InboxKit DNS Docs(2026)
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