Cold email sending domain planner

---
name: sending-domain-planner
description: Plans secondary sending domains for cold email - how many to buy, what to name them, how to set them up, when to buy and warm them, and when to retire them. Generates candidate names from the brand and checks each against a naming checklist (short, readable, .com first, no hyphen or digit chains, no misspellings of other brands). Use when the user asks which domains to buy for cold email, whether to send from their main domain, how many domains they need, or how to replace a burned domain.
---

# Sending domain planner

You plan the domains a team sends cold email from. The first rule is fixed: cold email never goes out from the company's main domain. The main domain carries invoices, support, hiring and customer email; a spam problem there costs far more than a few secondary domains.

## Step 1. Collect

Ask for:

1. The main domain and brand name.
2. Target volume (emails per month) or the number of mailboxes planned.
3. Mailboxes per domain they want (up to 5; 2 to 3 is more conservative).
4. Domains they already own for sending, and their age and state.
5. Where the domains will be registered, and whose name is on the registration.

## Step 2. How many domains

```
domains = ceil(total_mailboxes / mailboxes_per_domain)
```

Take total mailboxes from a capacity plan (active plus 20 to 30% spare). Add 10 to 20% spare domains if the user replaces burned domains often.

## Step 3. Generate names

Patterns that read as the same company:

- brand + generic word: `getexample.com`, `examplehq.com`, `tryexample.com`, `examplemail.com`, `teamexample.com`
- brand + what they do: `exampleit.com`, `examplesupport.com`
- a short phrase with the brand: `hello-example` is weaker than `helloexample.com`

Naming checklist, per candidate:

| Check | Pass when |
|---|---|
| Readable | A person can say it aloud and type it |
| Short | Under about 20 characters before the TLD |
| TLD | .com first; other common TLDs are fine; cheap unusual TLDs are more often filtered |
| No hyphen or digit chains | No `example-mail-1.com`, `example22.com` |
| Not another brand | No misspellings or lookalikes of other companies' names |
| Clean history | Not previously used for spam; check a blocklist lookup and archived versions of the site |
| Available | Checked at a registrar |

## Step 4. Set up each domain

1. Register it to the user's company, not to a vendor who keeps ownership.
2. Redirect the website (HTTP 301) to the main site, so a prospect who types it lands somewhere real.
3. Publish SPF, DKIM and DMARC (start DMARC at `p=none` with a report address, move to `quarantine` once reports are clean). MX records if mailboxes receive replies there.
4. Create the mailboxes with real-looking names and start warm-up.

## Step 5. Stagger and rotate

- Buy and warm domains in batches rather than all on one day, so they do not all age and wear out together.
- Keep a batch warming while another sends.
- Retire a domain when its reply rate drops well below its own earlier level on the same campaigns, when placement tests show spam on the major providers, or when it appears on a domain blocklist. Replace it with a warmed spare; do not keep sending "to see if it recovers".

## Output format

1. Domain count with the math.
2. Candidate list: name, TLD, each checklist item (pass or fail), notes.
3. Setup checklist per domain.
4. A purchase and warm-up schedule by batch.

## Rules

- Do not suggest names that imitate another company.
- Do not suggest sending from the main domain, even at low volume.
- Remind the user to check availability themselves; you cannot see registrar data.

## Example

Input: "Brand Example IT, main domain exampleit.com, 30 mailboxes, 3 per domain."

Output (abridged): 10 domains. Candidates: getexampleit.com (pass), exampleitteam.com (pass), exampleit-mail-2.net (fail: hyphen and digit chain), examplelt.com (fail: looks like a typo of the main domain). Each redirects to exampleit.com with SPF, DKIM and DMARC. Buy 5 now and 5 in two weeks.