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

# Sending Domains & DNS

> Verify the domain OpenCX sends email from — the exact DNS records to add, how verification works, and why a dedicated subdomain protects your main-domain reputation.

Before OpenCX can send email as your address, you verify the domain by adding a few DNS records. The **exact records — names, types, and values — are generated for your domain** under **[Settings → Domains](https://platform.open.cx/settings/domains)** (or via the [domain API](/api-reference/email/get_domains)); this page explains what they are and how to add them.

## Recommended: use a dedicated subdomain

We strongly recommend verifying a **subdomain** (e.g. `mail.yourcompany.com` or `support.yourcompany.com`) rather than your root domain:

* **Reputation isolation.** Sending reputation is tracked per domain. A dedicated subdomain keeps AI-agent and support traffic fully separate from your corporate mail — deliverability issues on one can never affect the other.
* **No conflicts.** The verification records live only on the subdomain, so nothing touches the SPF/DKIM/MX setup of your existing mail.
* **Same display address.** You can still send from any address on the verified domain (e.g. `support@mail.yourcompany.com`), and replies route back through your normal [forwarding setup](/email/forwarding).

## The DNS records

After adding a domain in **Settings → Domains**, you'll see a table of records to create at your DNS provider. Copy each one exactly as shown. The set is:

| Record | Type                                 | Purpose                                                                                                            |
| ------ | ------------------------------------ | ------------------------------------------------------------------------------------------------------------------ |
| SPF    | `TXT` (+ `MX` on a `send` subdomain) | Authorizes OpenCX to send mail on behalf of the domain.                                                            |
| DKIM   | `TXT`                                | Cryptographically signs outgoing mail so receivers can verify it wasn't altered and really comes from your domain. |

<Note>
  The record **names and values are unique to your domain** — always copy them from the dashboard rather than from documentation or another domain's setup.
</Note>

<Tip>
  **DMARC** is not required for verification, but if your organization enforces a DMARC policy on the root domain, verifying a subdomain (recommended above) means your policy is unaffected. If you want DMARC coverage on the sending subdomain itself, a standard `_dmarc` TXT record with `p=none` is a safe starting point.
</Tip>

## Verifying

<Steps>
  <Step title="Add the domain">
    In **[Settings → Domains](https://platform.open.cx/settings/domains)**, add the (sub)domain you want to send from. The required DNS records appear immediately.
  </Step>

  <Step title="Create the records at your DNS provider">
    Add each record with the exact name, type, and value shown. TTL can stay at your provider's default.
  </Step>

  <Step title="Run verification">
    Click **Verify** in the dashboard (or call the [verify API](/api-reference/email/patch_domains_verify)). DNS propagation usually takes minutes but can take up to 48 hours; each record shows its individual status, so you can see exactly which one is still pending.
  </Step>
</Steps>

Once the domain shows **Verified**, you can register sending addresses on it — continue with [Connect Email](/email/forwarding).

## Related Documentation

<CardGroup cols={2}>
  <Card title="Connect Email" icon="paper-plane" href="/email/forwarding">
    Register your support address and set up forwarding.
  </Card>

  <Card title="Domain API" icon="code" href="/api-reference/email/get_domains">
    Manage domains and read record status programmatically.
  </Card>
</CardGroup>