---
title: "Cold Email Infrastructure Planner Claude Skill"
description: "A Claude skill that turns a target send volume into mailboxes, domains and cost, and compares prewarmed against fresh on cost per email actually delivered."
url: https://warminboxes.com/skills/infrastructure-planner
breadcrumb: "Home > Claude Skills > Infrastructure Planner"
---
Claude skill

# Infrastructure Planner

How many mailboxes do I need, and what does it cost?

Turns “I want to send 10,000 a day” into a number of mailboxes, a number of domains, a monthly cost, and a date by which it is actually sending. It always runs the comparison twice, because prewarmed and fresh are not the same purchase and the cheaper per-inbox price is not always the cheaper campaign.

## What it runs

- **Volume to mailboxes** — At a sane number of sends per mailbox per day

- **Mailboxes to domains** — At the ratio that keeps a single domain from carrying the whole fleet

- **Platform** — Google, Microsoft 365 or an isolated Azure tenant, and what each is for

- **Prewarmed against fresh** — Cost per email actually delivered over the window you care about, not cost per inbox

- **Warmup time** — The 14–21 days fresh spends not sending, which is where the real cost hides

## What you get back

- Mailboxes, domains, monthly capacity and cost

- The assumptions it used, stated out loud, because those are the numbers people disagree about

- Prewarmed and fresh side by side on delivered-email cost, with the arithmetic shown

- A first-send date, which is the number fresh pricing tends to hide

## Install it

One file, from GitHub. It calls the free WarmInboxes API, so there is no key and nothing to sign up for.

 mkdir -p ~/.claude/skills/infrastructure-planner
curl -sL https://raw.githubusercontent.com/Huz-ai-fa/warminboxes-claude-skills/main/infrastructure-planner/SKILL.md -o ~/.claude/skills/infrastructure-planner/SKILL.md

[View it on GitHub →](https://github.com/Huz-ai-fa/warminboxes-claude-skills/tree/main/infrastructure-planner)

## Then just ask

You do not name the skill. Its description tells Claude when it applies.

- "How many inboxes do I need to send 10,000 cold emails a day?"

- "What does cold email infrastructure cost for 5,000 sends a day?"

- "Should I buy prewarmed or fresh inboxes?"

Every answer cites the check behind it, so anything Claude tells you can be re-run by hand. A clean result is reported clean, with nothing to buy.

[All Claude skills →](https://warminboxes.com/skills)

## Do it by hand

The same checks as free tools in a browser.

- [Infrastructure Calculator](https://warminboxes.com/calculator)

- [Domain & Inbox Planner](https://warminboxes.com/inbox-planner)

- [Inbox Rotation Planner](https://warminboxes.com/inbox-rotation-planner)

## The other skills

One page each.

- [Inbox Checker](https://warminboxes.com/skills/inbox-checker) — Is this domain burned?

- [Domain Audit](https://warminboxes.com/skills/domain-audit) — Is this domain set up correctly to send from?

- [List Segmentation](https://warminboxes.com/skills/list-segmentation) — Who hosts the people on this list?