Custom receiving domains

Besides MailBlastr-managed domains, you can receive email on your own custom domain such as yourdomain.tld. Receiving on a custom domain takes one extra DNS record — an MX record — on top of the verification you already do for sending.

1. Add the MX record

First, verify your domain for sending if you have not already. Receiving then requires an additional MX record so mail for the domain is routed to MailBlastr:

1. 1
   Open Domains

   Go to the Domains page in the dashboard and open the domain you want to receive on.

2. 2
   Copy the MX record

   In the receiving section, copy the MX record MailBlastr shows you (host and priority).

3. 3
   Add it at your DNS provider

   Paste the MX record into your DNS provider and save.

2. Configure a webhook

Create a webhook endpoint subscribed to the email.received event, exactly as for a managed domain:

1. 1
   Open Webhooks

   Go to the Webhooks page in the dashboard.

2. 2
   Add a webhook

   Click "Add Webhook" and enter your endpoint URL.

3. 3
   Subscribe to email.received

   Select the email.received event type and save.

3. Receive email events

Create a route that accepts POST requests and handles the email.received event:

// app/api/events/route.ts
import type { NextRequest } from 'next/server';
import { NextResponse } from 'next/server';

export const POST = async (request: NextRequest) => {
  const event = await request.json();

  if (event.type === 'email.received') {
    return NextResponse.json(event);
  }

  return NextResponse.json({});
};

After receiving the event you can fetch the message body and attachments. We recommend verifying the webhook signature to secure your endpoint. The email.received payload shape is identical to a managed domain:

{
  "type": "email.received",
  "created_at": "2026-02-22T23:41:12.126Z",
  "data": {
    "email_id": "56761188-7520-42d8-8898-ff6fc54ce618",
    "created_at": "2026-02-22T23:41:11.894719+00:00",
    "from": "onboarding@mailblastr.dev",
    "to": ["delivered@mailblastr.dev"],
    "bcc": [],
    "cc": [],
    "received_for": ["forwarded@example.com"],
    "message_id": "<111-222-333@email.example.com>",
    "subject": "Sending this example",
    "attachments": [
      {
        "id": "2a0c9ce0-3112-4728-976e-47ddcd16a318",
        "filename": "avatar.png",
        "content_type": "image/png",
        "content_disposition": "inline",
        "content_id": "img001"
      }
    ]
  }
}

Enabling receiving for an existing domain

If you already have a verified domain, enable receiving with the toggle in the receiving section of the domain detail page. A modal then shows the MX record to add at your DNS provider. After you add it, click "I've added the record" and wait for the receiving record to show as verified.

FAQ

What if I already have MX records for my domain?

Mail is delivered only to the MX record with the lowest priority value. Adding MailBlastr's MX record to a root domain that already has MX records will either receive nothing (if the existing record is lower priority) or hijack your existing email (if MailBlastr's is lower priority); equal priorities make delivery unpredictable. The safe choice is a dedicated subdomain such as subdomain.yourdomain.tld. Alternatively, keep using the same domain for both: set up a forwarding rule in your existing email service that forwards to an address configured in MailBlastr, or forwards directly to the SMTP server hostname that appears in the receiving MX record.

Do I need to verify the domain again for receiving?

No. A domain already verified for sending only needs receiving enabled and the new MX record added — MailBlastr verifies that one record.