Adds one or more mailboxes for the authenticated client.

Email Validation

• Email format is validated (must be valid RFC format)
• Email is automatically normalized (lowercase)

Domain Validation

• Domain must exist and belong to the authenticated client
• Mailboxes can be added when the domain is pending, in_progress, or active
• Only inactive domains are rejected
• Missing domain names are returned in the error
• inactive domain names are returned in the error (DOMAIN_INACTIVE)

Mailbox Limits

• Maximum mailboxes per domain: 3
• If limit would be exceeded, error is returned with details

Duplicate Check

• Email addresses must be unique within a domain
• If duplicates exist, all duplicate emails are returned in the error

Default Settings

• All new mailboxes have status set to pending

{
  "mailboxes": [
    {
      "email": "john.doe@example.com",
      "first_name": "John",
      "last_name": "Doe"
    }
  ]
}

{
  "success": true,
  "data": {
    "added_count": 5,
    "mailboxes": [
      {
        "id": 456,
        "email": "john.doe@example.com",
        "domain_id": 123,
        "status": "pending"
      }
    ]
  },
  "timestamp": "2025-12-14T10:30:00Z"
}