Multi-server

Postal scopes API keys to a mail server (usually one per product or sending domain). Configure one entry per server:

'default' => env('POSTAL_SERVER', 'cbox-id'),

'servers' => [
    'cbox-id' => [
        'url' => env('POSTAL_CBOX_ID_URL', 'https://postal.cbox.dk'),
        'key' => env('POSTAL_CBOX_ID_KEY'),
    ],
    'cbox-billing' => [
        'url' => env('POSTAL_CBOX_BILLING_URL', 'https://postal.cbox.dk'),
        'key' => env('POSTAL_CBOX_BILLING_KEY'),
    ],
],

Only list the servers an app actually sends through — the config is the allow-list; unknown names are rejected everywhere (client, webhooks, commands).

Addressing a server

Postal::send(...);                          // default server
Postal::server('cbox-billing')->send(...);  // explicit

Mail transport per mailer:

'mailers' => [
    'postal' => ['transport' => 'postal'],                              // default server
    'postal-billing' => ['transport' => 'postal', 'server' => 'cbox-billing'],
],

Notifications pick a server by implementing postalServer($notifiable) — see Notifications.

Webhooks

Each Postal mail server has its own webhook configuration. Point each one at its named endpoint so events are attributed correctly:

https://your-app.example/postal/webhook/cbox-id
https://your-app.example/postal/webhook/cbox-billing

postal:ping (no argument) verifies all configured servers at once.