# Cold email for your AI agent: the domain, the inboxes, the warm-up and the send

RouterGrowth gives an agent the whole cold email stack through one MCP server: find and register a sending domain, write its DNS records, create inboxes, warm them up, send, and read the replies. It is the infrastructure an agent needs to run outbound from zero, on one balance.

HTML page: https://www.routergrowth.com/tools/cold-email

## What your agent can do

| Capability | What it returns | Providers | From | Status |
|---|---|---|---|---|
| [`domain.search`](https://www.routergrowth.com/catalog/domain.search) | Check which domains are available and what they cost to register through RouterGrowth: a name across common TLDs, or one exact domain. | Name.com | $0.002 per search | live |
| [`domain.register`](https://www.routergrowth.com/catalog/domain.register) | Buy a domain for outbound sending. Registered in RouterGrowth's registrar account with you as the registrant contact; WHOIS privacy on; transferable to you on request. | Name.com | $21 per domain | live |
| [`domain.dns`](https://www.routergrowth.com/catalog/domain.dns) | Create DNS records on a domain registered through RouterGrowth: the records email.domain asks for, or anything else. | Name.com | $0.002 per call | live |
| [`email.domain`](https://www.routergrowth.com/catalog/email.domain) | Bring your own domain for outbound: registers it, returns the DNS records and a one-click setup link, and reports verification status. Run again to re-check. | AgentMail | $2.3275 per domain | live |
| [`email.inbox`](https://www.routergrowth.com/catalog/email.inbox) | Create (or fetch) a sending inbox owned by your organization on a domain you verified with email.domain: name + domain, idempotent. Or rename one you own: inbox_id + display_name sets the From name on everything it sends (free). Run email.inboxes first to see what you already own. | AgentMail | $2.3275 per inbox | live |
| [`email.warmup`](https://www.routergrowth.com/catalog/email.warmup) | Warm up one of your inboxes before cold sending: a network of real mailboxes sends to it, opens, replies and pulls its mail out of spam, on a ramp to the daily volume you set, weekdays 8am to 6pm. action start (run it again to change volume, ramp or timezone), pause, resume or stop. Charged per inbox per 30 days by daily volume; progress is free with email.warmup_status. | Mailivery | $9.3275 per inbox month | live |
| [`email.warmup_status`](https://www.routergrowth.com/catalog/email.warmup_status) | How your inbox warm-ups are doing. Without inbox_id: every warm-up with its status, daily volume and ramp-up day. With inbox_id: that inbox's health grade (SPF, DMARC, MX, domain age) and where its warm-up mail landed over the last 14 days, inbox or spam. Free. | Mailivery | $0 per call | live |
| [`email.send`](https://www.routergrowth.com/catalog/email.send) | Send an email from one of your inboxes, or reply within a thread, with file attachments when needed (a deck, a PDF: by public https url, or inline as base64). You are the sender of record: consent and unsubscribe handling are yours. | AgentMail | $0.0035 per email | live |
| [`email.messages`](https://www.routergrowth.com/catalog/email.messages) | Messages in one of your inboxes, newest first, sent and received alike: a 200-character preview each, with direction and a bounced flag (a hard bounce is a label on your own sent message). Pass message_id to read one message in full. Poll it after a send. | AgentMail | $0.002 per read | live |
| [`email.inboxes`](https://www.routergrowth.com/catalog/email.inboxes) | The sending domains and inboxes this workspace already owns, with each domain's verification status and each inbox's inbox_id. Free. Run it before creating an inbox or sending, so you reuse what exists. | AgentMail | $0 per call | live |

## Ask it like this

- Set me up for cold email from zero: find a domain close to ours, register it, create three inboxes and start warming them. (`domain.search`, `domain.register`, `domain.dns`, `email.inbox`, `email.warmup`)
- Send this three-step sequence to the 200 verified contacts on my list, 30 a day per inbox. (`email.send`)
- Read the replies from this week and tell me who is interested. (`email.messages`)

## Connect

MCP server: `https://api.routergrowth.com/mcp` (OAuth, or an API key header).

```bash
claude mcp add --transport http routergrowth https://api.routergrowth.com/mcp
```

```bash
npm install -g routergrowth && routergrowth setup
routergrowth run -c domain.search -i '{"name": "getacme", "tlds": ["com", "io"]}'
```

```bash
curl -X POST https://api.routergrowth.com/v1/run \
  -H "Authorization: Bearer $ROUTERGROWTH_API_KEY" \
  -d '{"capability": "domain.search", "input": {"name": "getacme", "tlds": ["com", "io"]}}'
```

## Worth knowing

- **Yours to keep.** The domain is registered with you as the registrant contact and can be transferred to you, and the inboxes belong to your workspace. You are the sender of record.
- **Warm-up before volume.** A network of real mailboxes exchanges mail with each inbox on a ramp. email.warmup_status shows where that mail landed, inbox or spam.
- **A separate domain on purpose.** Cold sequences go out from a second domain so your main one keeps its reputation.

## Questions

### What tools do I need for cold email?

A sending domain, inboxes on it, warm-up, a sender and a way to read replies. Here they are capabilities on one key, so an agent sets the whole thing up and runs it.

### Can an AI agent buy a domain and set up inboxes?

Yes. domain.search finds an available name, domain.register buys it, domain.dns writes the records and email.inbox creates the mailboxes.

### How does email warm-up work?

email.warmup enrols an inbox in a network of real mailboxes that send to it, open, reply and move its mail out of spam, ramping to the daily volume you set.

### How many emails can I send a day?

The usual practice is about 30 a day per warmed inbox. The agent adds inboxes to reach the volume you need.

### Who is responsible for consent and unsubscribes?

You are. The mail goes out from your domain and your inboxes, and the rules that apply to your recipients are yours to follow.

## Related

- Workflow: [Email finance leaders at UK companies hiring accountants](https://www.routergrowth.com/workflows/hiring-uk-finance.md)
- Workflow: [Reach sales leaders at companies hiring SDRs](https://www.routergrowth.com/workflows/hiring-sdr-teams.md)
- Workflow: [Book demos with CTOs at SaaS companies that just raised a Series A](https://www.routergrowth.com/workflows/funding-series-a-ctos.md)
- Workflow: [Email founders of seed-stage startups that raised this quarter](https://www.routergrowth.com/workflows/funding-seed-founders.md)
- Workflow: [Reach founders of Shopify stores with 50 to 500 employees](https://www.routergrowth.com/workflows/technology-shopify-plus-owners.md)
- Workflow: [Reach RevOps leaders at companies that use HubSpot](https://www.routergrowth.com/workflows/technology-hubspot-revops.md)
- Guide: [Cold email infrastructure: domains, DNS, inboxes and warm-up from one API](https://www.routergrowth.com/use-cases/cold-email-infrastructure.md)
- Guide: [Instantly MCP: what the official server does, how to connect it, and an alternative for agents starting from zero](https://www.routergrowth.com/use-cases/instantly-mcp.md)
- Skill: [Cold email pipeline](https://www.routergrowth.com/skills/cold-email-pipeline.md)
- Skill: [SDR daily](https://www.routergrowth.com/skills/sdr-daily.md)