How do I queue mail in Laravel 12 without Horizon?

You do not need Redis or Horizon. The database queue driver is enough for most small and mid-size apps.

1. Create the jobs table

php artisan make:queue-table   # skip if the jobs migration already exists
php artisan make:queue-failed-table
php artisan migrate

New Laravel 12 apps already ship the jobs and failed_jobs migrations and default to QUEUE_CONNECTION=database. Check .env.

2. Queue the mail

Mail::to($user)->queue(new Welcome($user));

queue() replaces send(). Alternatively make the mailable implement ShouldQueue, then even send() is queued.

class Welcome extends Mailable implements ShouldQueue
{
    use Queueable, SerializesModels;
}

3. Run a worker

php artisan queue:work --tries=3 --backoff=30

Locally this is enough. On a server, keep it alive with Supervisor (VPS) or a cron-driven worker on shared hosting:

* * * * * cd /path/to/app && php artisan queue:work --stop-when-empty --max-time=55 >> /dev/null 2>&1

Common pitfalls

• With QUEUE_CONNECTION=sync (the old default) nothing is actually queued.
• Workers are long-running processes and keep old code in memory. Run php artisan queue:restart after every deploy.
• Pass models, not huge arrays, and let SerializesModels reload them. If the row is deleted before the job runs you get a ModelNotFoundException.
• Use ->afterCommit() or public $afterCommit = true; if you queue inside a DB transaction, otherwise the worker may run before the data is committed.

There is also a ready-made example of throttled queued sending in the DEV3 snippet library.