> ## Documentation Index
> Fetch the complete documentation index at: https://docs.recepta.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Email infrastructure

> Sending domains, mailboxes, warmup, and the rules that keep campaign email landing.

Campaign email needs its own sending setup. Send cold volume from the domain you invoice customers from and a deliverability problem takes your business email down with it.

Recepta.ai keeps them separate: dedicated sending domains and mailboxes for outbound, warmed independently, with your primary domain untouched.

## Sending domains

A sending domain is a domain used only for campaign email. Typically a close variant of your main one — if you're `coralplumbing.com`, something like `getcoralplumbing.com` or `coralplumbing.co`.

<Warning>
  Never use your primary business domain for cold outbound. If its reputation is damaged, your quotes, invoices, and customer replies stop arriving — far more costly than a slow campaign.
</Warning>

Each domain needs its authentication records in place before it sends anything:

| Record | Purpose                                           |
| ------ | ------------------------------------------------- |
| SPF    | Declares which servers may send for the domain    |
| DKIM   | Cryptographically signs your mail                 |
| DMARC  | Tells receivers what to do when SPF or DKIM fails |

Recepta.ai provides the records to add at your DNS provider and verifies them once they've propagated. All three must pass — a domain missing DKIM will be filtered regardless of how good the message is.

## Mailboxes

Each sending domain carries one or more mailboxes — the individual addresses campaign email is sent from. Spreading volume across several mailboxes keeps per-mailbox volume in a range that looks like a person rather than a broadcast.

<Note>
  Use real human names on mailboxes. `dan@` outperforms `info@` or `sales@`, which are heavily filtered and rarely replied to.
</Note>

## Warmup

A brand new domain has no sending reputation. Send a thousand emails from it on day one and providers treat it as a spam source — sometimes permanently.

Warmup builds reputation gradually, with volume ramping over weeks rather than days.

<Warning>
  Warm every new domain and mailbox before campaign use, and don't shortcut the ramp. A burned domain is not really recoverable — you buy another one and start again.
</Warning>

<Steps>
  <Step title="Register the domain and set DNS">
    SPF, DKIM, and DMARC. Allow time for propagation.
  </Step>

  <Step title="Create mailboxes">
    Real names, with a signature and a plausible profile.
  </Step>

  <Step title="Run warmup">
    Let it build for several weeks before real campaign volume.
  </Step>

  <Step title="Ramp campaigns slowly">
    Start well below the mailbox's warmed volume and increase over days.
  </Step>
</Steps>

## Staying deliverable

<Columns cols={2}>
  <Card title="List quality first" icon="filter">
    Bad addresses produce bounces, and bounce rate is the fastest way to wreck a domain. Never send to a purchased list.
  </Card>

  <Card title="Watch complaints" icon="triangle-exclamation">
    Spam complaints are weighted heavily. If they rise, stop and fix the targeting rather than pushing more volume.
  </Card>

  <Card title="Make unsubscribe easy" icon="square-check">
    A visible, working unsubscribe costs one contact. A hidden one earns a spam complaint, which costs the whole domain.
  </Card>

  <Card title="Write like a person" icon="pen">
    Short, plain, specific, few links. Heavy formatting and image-only mail filters badly.
  </Card>
</Columns>

## Compliance

CAN-SPAM requires accurate sender information, a physical mailing address, no misleading subject lines, and a working unsubscribe honored promptly. Recepta.ai suppresses unsubscribed addresses permanently and across all campaigns.

<Warning>
  Re-importing a suppressed address to send to it again is a violation, and it damages every domain you send from. See [Contacts](/outbound/contacts).
</Warning>

## Transactional email is different

Appointment confirmations, reminders, and customer replies aren't campaign email and don't run on this infrastructure. See [Email inbox](/channels/email-inbox).