# Inbox Setup

> Set up cold email inbox infrastructure from scratch — Google Workspace, Microsoft 365, and Azure/Entra inbox provisioning, DNS authentication, domain buying, warmup, and cost optimization. Use when setting up sending infrastructure, buying domains, provisioning mailboxes, or scaling cold email sending capacity. Triggers on: "inbox setup", "email infrastructure", "buy domains", "Google Workspace inbox", "Microsoft inbox", "Azure inbox", "cold email setup", "sending infrastructure", "provision inboxes", "DNS setup", or any request about building cold email infra.

- Skill: `leadmagic/inbox-setup` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add leadmagic/inbox-setup`
- Raw SKILL.md: https://api.skillmd.com/api/skills/leadmagic/inbox-setup/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- License: MIT
- Author: LeadMagic (https://skillmd.com/u/leadmagic)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/leadmagic/inbox-setup

---


# Inbox Setup

## Overview

Cold email infrastructure is the foundation underneath every outbound motion.
Get it wrong and your copy, targeting, and offer don't matter — you're in spam.
This skill covers DIY inbox provisioning across Google Workspace, Microsoft 365,
and Azure/Entra, plus DNS authentication, warmup, and infrastructure scaling.

## When to Use

- "Set up cold email inboxes"
- "Buy domains for cold outreach"
- "Provision Google Workspace mailboxes"
- "Set up Microsoft 365 for cold email"
- "Configure DNS for sending domains"
- "Scale my sending infrastructure"
- "How many inboxes do I need?"

## Authoritative Foundations

- **Google Bulk Sender Guidelines** — sender authentication, low spam complaint rates, and authenticated alignment are baseline requirements for sustainable outbound.
  Domain isolation is non-negotiable: never send cold from the primary business domain; use separate sending domains with independent reputation.
- **Microsoft Email Sender Guidelines** — maintain authenticated mail, clean lists, low complaints, and conservative volume ramps to protect sender reputation.
- **Eric Nowoslawski (Growth Engine X)** — inbox infrastructure at scale
  emails/month. Strategy: 2 inboxes per domain, 30 emails/day per inbox,
  3-week warmup minimum, keep 50% spare capacity warming at all times.
- **Jed Mahrle (Practical Prospecting)** — 30,000+ subscribers. "Cold email
  isn't a numbers game anymore. It's a relevance game. Send fewer emails to
  better fit accounts."

## Prerequisites

- Domain registrar account (Namecheap, GoDaddy, Google Domains)
- Google Workspace or Microsoft 365 tenant (or Azure/Entra for Hypertide-style)
- DNS management access
- Budget: ~$6-15/mailbox/month for Google, ~$4-6/mailbox/month for Microsoft,
  plus domain costs (~$10-15/domain/year)

## Step-by-Step Process

### Phase 1: Domain Acquisition

Buy 3-5 secondary domains for cold outreach. Never use your primary business domain.

**Rules:**
- .com or .co preferred — avoid unusual TLDs that trigger spam filters
- Domain should be a variation that could be a real company (e.g., tryacme.com,
  getacme.io, acmehq.com)
- Redirect the domain to your main site or a simple landing page
- Set up SSL certificate (Let's Encrypt, free)

**Cost:** ~$10-15/domain/year. Budget 3-5 domains = $30-75/year.

### Phase 2: Mailbox Provider Selection

| Provider | Cost/Mailbox | Mailboxes/Domain | Sends/Day/Mailbox | Best For |
|---|---|---|---|---|
| **Google Workspace** | $6-15/mo | 2-3 | 25-30 | Highest deliverability, preferred by Google recipients |
| **Microsoft 365** | $4-6/mo | 25 | 10 | High deliverability to Outlook, best mailbox-to-domain ratio |
| **Azure/Entra (via Hypertide)** | $50/order (100 inboxes) | 50 | 2 (after warmup) | Maximum scale, lowest cost per inbox |
| **SMTP (via ScaledMail)** | $3.50-4/mo | 4 | 10 | Budget option, works with any sequencer |

**Eric Nowoslawski Strategy:** 2 inboxes per domain, 30 sends/day/inbox, 3-week
warmup minimum. Keep 50% spare capacity warming at all times.

**Scaling math:** To send 1,000 emails/day:
- Google: 1,000 ÷ 25 = 40 inboxes, 20 domains, ~$240-600/mo
- Microsoft: 1,000 ÷ 10 = 100 inboxes, 4 domains, ~$400-600/mo
- Hypertide Entra: 1,000 ÷ 2 = 500 inboxes, 10 orders, ~$500/mo + setup

### Phase 3: DNS Authentication (Non-Negotiable)

For every sending domain, configure all three:

**SPF:** `v=spf1 include:_spf.google.com ~all` (Google) or
`v=spf1 include:spf.protection.outlook.com ~all` (Microsoft)

**DKIM:** Generate in admin console (Google: Apps > Gmail > Authenticate email.
Microsoft: Security > DKIM). Add the generated TXT record to DNS.

**DMARC:** Start with `v=DMARC1; p=none; rua=mailto:person@example.com`.
After monitoring for 2-4 weeks, tighten to `p=quarantine`, eventually `p=reject`.

**Verification:** Use MXToolbox or Google Admin Toolbox to verify all records
resolve correctly. A single misconfigured record = spam placement.

### Phase 4: Warmup (2-4 Weeks Minimum)

- Week 1: 5-10 emails/day to known-engaging addresses
- Week 2: 15-25 emails/day, mix warm and cold
- Week 3: 30-40 emails/day
- Week 4: 40-50 emails/day, full cold sending

Use a dedicated warmup tool (Instantly Warmup, Smartlead Warmup, or
Hypertide's built-in warmup). Monitor inbox placement weekly.

**Eric Nowoslawski note:** "We used to be able to launch low volume without
waiting 3 weeks. These days, inboxes may not be ready even after a full 3
weeks." Plan conservatively.

### Phase 5: Infrastructure Players

| Provider | What They Do | Best For |
|---|---|---|
| **ScaledMail** | Done-for-you inbox provisioning. Google, M365, SMTP. 230K+ inboxes managed. | Teams that want hands-off setup |
| **Hypertide** | Automated Azure/Entra inboxes in 4-6 hours. Tenant isolation. $50/mo per 100 inboxes. | High-volume agencies, max scale |
| **Mailforge** | Full DNS monitoring, custom warmup, inbox health reports | Teams that want control + visibility |
| **Maildoso** | Pre-configured inboxes + domains + DNS. Master inboxes. | Budget-conscious teams |

**DIY vs Done-For-You:** DIY costs less per mailbox but requires 4-8 hours of
setup plus ongoing maintenance. Done-for-you (ScaledMail, Hypertide) costs
more per mailbox but ships in hours to days. The breakeven: if your time is
worth >$100/hr, done-for-you wins at any scale.

## Output Format

Infrastructure plan with: domain inventory, mailbox count by provider, DNS
record sheet, warmup schedule, cost model (setup + monthly), and monitoring
dashboard setup.

## Quality Check

- [ ] No primary business domain used for cold sending
- [ ] SPF, DKIM, DMARC configured and verified on every domain
- [ ] 2-3 inboxes per domain maximum (Google) or 25 (Microsoft)
- [ ] 30-50 sends/day/inbox maximum
- [ ] 2-4 week warmup completed before any cold sends
- [ ] 50% spare capacity warming at all times
- [ ] MXToolbox or equivalent verification passed on all domains

## Common Pitfalls

1. **Sending from primary domain.** One spam complaint and your password
   resets, invoices, and support emails go to spam too. Never.

2. **Too many inboxes per domain.** 10+ mailboxes on one domain signals
   bulk sending to spam filters. 2-3 for Google, 25 max for Microsoft.

3. **Skipping warmup.** New domains sent at full volume get blacklisted
   within 48 hours. There is no shortcut.

4. **Sending unverified emails.** 5%+ bounce rate triggers automated spam
   filtering. Always verify with a service like LeadMagic Email Validation
   before sending.

5. **No spare capacity.** If inboxes burn out mid-campaign and you have no
   spares warming, your pipeline stops. Keep 50% spare capacity.

6. **DNS misconfiguration.** A missing DKIM record or incorrect SPF syntax
   is caught by every major inbox provider. Triple-check all records.

## Execution Artifacts

- `references/framework-notes.md` — Named frameworks and reference tables
- `templates/output-template.md` — Deliverable shell for agent output
- `scripts/check-output.py` — Lightweight deliverable validator
- `../cold-email-strategy/references/eric-nowoslawski-outbound.md` — Sending volume strategy, 1:1 backups (Eric Nowoslawski)

## Related Skills

- **email-deliverability**: Full deliverability strategy beyond infrastructure
- **domain-infrastructure**: DNS auth deep-dive
- **sending-platforms**: Sequencer selection and setup
- **contact-verification**: Verify emails before they enter your inboxes