How to Send Cold Emails: The Complete Infrastructure-to-Campaign Guide

If you want to send cold emails that actually land in the inbox and generate replies, you need more than a good subject line. You need the right infrastructure, the right tools, and a process that protects your sender reputation from day one.

This guide walks you through every step — from purchasing domains to launching your first campaign — so you can send cold emails with confidence.

Step 1: Buy Secondary Domains

Never send cold emails from your primary business domain. If your company domain is `acme.com`, register variations like `acme-mail.com`, `getacme.com`, or `tryacme.com`. Buy 3-5 domains to start. Each domain can support 2-3 mailboxes, giving you 6-15 sending accounts.

Why multiple domains? If one domain gets flagged, your main brand stays untouched. This is non-negotiable for anyone serious about cold outreach.

Step 2: Set Up Email Accounts

You have two main options for hosting your mailboxes:

• Google Workspace — $7.20/user/month, excellent deliverability baseline, widely trusted by spam filters
• Microsoft 365 (Outlook) — $6/user/month, good alternative, sometimes better for enterprise-heavy prospect lists

Create 2-3 mailboxes per domain. Use real-sounding names like `james@getacme.com`, not `sales@` or `noreply@`. Read our Google Workspace vs Outlook comparison for a detailed breakdown.

Step 3: Configure DNS Authentication

Before sending a single email, configure three DNS records for every domain:

1. SPF — Tells receiving servers which IPs are allowed to send on your behalf. Add a TXT record like `v=spf1 include:_spf.google.com ~all`.
2. DKIM — Adds a cryptographic signature to each email proving it hasn't been tampered with. Google Workspace and Microsoft 365 both provide DKIM keys in their admin panels.
3. DMARC — Instructs receivers what to do when SPF or DKIM fails. Start with `v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com` and tighten the policy over time.

Our SPF, DKIM & DMARC setup guide covers this in detail. You can also use Mail-Tester or GlockApps to verify your configuration.

Step 4: Warm Up Your Mailboxes

Brand-new mailboxes have zero reputation. If you start blasting 50 emails a day immediately, you will land in spam. Email warmup is the process of gradually building sender reputation by exchanging emails with a network of real inboxes.

The best warmup tools:

• Instantly — Has built-in warmup included with every plan
• Warmbox — Dedicated warmup tool, very effective for high-volume senders
• MailReach — Strong deliverability monitoring alongside warmup

Warm up for a minimum of 14 days before sending any cold emails. Start at 5 emails/day and ramp to 30-40/day over two weeks.

Step 5: Build and Verify Your Prospect List

Your list quality directly determines your results. A 5% bounce rate can damage your domain reputation. Always verify your list before sending.

Use verification tools like ZeroBounce or NeverBounce to remove invalid addresses. Aim for a bounce rate under 2%.

For finding prospects, tools like Apollo combine prospecting with verified email data, reducing the need for a separate verification step.

Step 6: Choose a Sending Platform

Do not send cold emails from Gmail or Outlook directly. Use a dedicated cold email platform that handles throttling, rotation, and tracking:

See our Compare Tools page to evaluate these side-by-side.

Step 7: Write Your Sequences

A cold email sequence typically has 3-5 touchpoints spaced 3-4 days apart. Key principles:

• Keep it short — Under 100 words for the first email
• Personalize the first line — Reference something specific about the prospect's company
• One clear CTA — Ask for a 15-minute call, not a novel
• Use spintax — Vary phrasing across emails to avoid pattern detection by spam filters

Check out our cold email examples for proven templates.

Step 8: Launch, Monitor, and Iterate

Start with 20-30 emails per mailbox per day. Monitor your spam score using GlockApps or Mail-Tester.

Key metrics to track:

• Open rate — Below 40%? Your subject line or deliverability needs work
• Reply rate — 3-8% is typical for cold email
• Bounce rate — Keep under 2% or pause and re-verify your list

Use our Stack Builder to assemble the perfect tool combination for your sending volume and budget.

Common Mistakes When You Send Cold Emails

1. Sending from your main domain — One spam complaint can tank your business email
2. Skipping warmup — Even great copy fails from a cold mailbox
3. No SPF/DKIM/DMARC — These are table stakes in 2026
4. Buying cheap, unverified lists — High bounce rates destroy reputation fast
5. Sending too many emails too soon — Patience in the first 30 days pays off

Ready to send cold emails that actually get replies? Browse all our recommended tools by category to build your complete cold email stack.