The email infrastructure guide for serious cold email operations.
Your sending infrastructure is the foundation of every campaign. Set it up wrong and nothing else matters. This guide covers the full stack from domain purchase to ongoing monitoring.
Infrastructure is the foundation
Most cold email failures are infrastructure failures. The copy is fine. The list is fine. But the emails land in spam because the domains aren't warmed, the DNS is misconfigured, the sending volume is too high too fast, or the bounce rate spiked and tanked reputation. This guide walks through every layer of the sending infrastructure stack -- what to set up, how to configure it, and how to maintain it over time.
What's in this guide
- Domain strategy: how many to buy, naming conventions, registrar selection
- Mailbox setup: provider selection, account creation, forwarding configuration
- DNS authentication: SPF, DKIM, DMARC, BIMI, custom tracking domains
- Warmup protocol: 14-day schedule with daily volume targets
- Sending platform configuration and inbox rotation
- Bounce handling: hard vs. soft bounces, threshold management
- Monitoring setup: seed testing, blocklist scanning, reputation tracking
- Rotation schedule: when to retire and replace domains
Where to go from here
This guide covers the technical setup. For the strategy layer -- targeting, copy, sequencing, and optimization -- see our Outbound Playbook. For warmup specifics, see our Domain Warmup Guide. For ongoing deliverability maintenance, check our Deliverability Guide. Or let us build and manage your infrastructure -- it's our core competency.
Frequently asked questions
How much does a proper infrastructure setup cost?
For a typical campaign: 3-5 domains ($10-15 each), 9-15 mailboxes ($2-6/month each), sending platform ($30-100/month), and monitoring tools ($50-100/month). Total: roughly $150-400/month for infrastructure alone.
Can I use my primary domain for cold email?
Never. Cold email should always use separate sending domains that protect your primary domain reputation. If a sending domain gets burned, your company email and website are unaffected.
How often should I rotate domains?
Depends on volume and health signals. At moderate volume (5,000-10,000 emails/month), domains last 3-6 months. At higher volumes or with any reputation issues, rotate more frequently. Always have backup domains warming.
Let us handle the infrastructure.
Book a call and we'll build, manage, and monitor your entire sending stack.