Queued notifications in Laravel - Step-by-Step Execution

Concept Flow - Queued notifications

Trigger Notification Event

↓

Create Notification Instance

↓

Queue Notification Job

↓

Worker Picks Job from Queue

↓

Send Notification (Email, SMS, etc.)

↓

Mark Job as Completed

↓

Done

This flow shows how Laravel queues a notification: event triggers, notification is queued, a worker sends it, then marks it done.

Execution Sample

Laravel

Notification::route('mail', '[e-mail]')
    ->notify(new InvoicePaid($invoice));

This code sends a notification to an email address using Laravel's notification system, which can be queued.

Execution Table

Step	Action	Queue State	Worker Action	Notification Status
1	Trigger notification	Empty	Idle	Not sent
2	Create notification instance	Empty	Idle	Not sent
3	Queue notification job	Job added to queue	Idle	Queued
4	Worker picks job	Job removed from queue	Processing job	Sending
5	Send notification	Empty	Sending email to [e-mail]	Sent
6	Mark job completed	Empty	Idle	Completed

💡 Notification job processed and marked completed, queue is empty

Variable Tracker

Variable	Start	After Step 3	After Step 4	After Step 6
Queue	Empty	1 job	Empty	Empty
Worker	Idle	Idle	Processing job	Idle
Notification Status	Not sent	Queued	Sending	Completed

Key Moments - 3 Insights

Why does the notification not send immediately after calling notify()?

Because the notification is queued as a job (see Step 3 in execution_table), it waits in the queue until a worker processes it.

What happens if no worker is running?

The job stays in the queue (Step 3), and the notification remains unsent until a worker picks it up (Step 4).

How does Laravel know which channel to use for sending?

The notification class defines channels (mail, SMS, etc.), and the worker uses this info during sending (Step 5).

Visual Quiz - 3 Questions

Look at the execution_table, what is the Queue State after Step 3?

A Empty

B Job added to queue

C Job removed from queue

D Processing job

💡 Hint

Check the 'Queue State' column at Step 3 in the execution_table.

At which step does the worker start processing the notification job?

A Step 2

B Step 3

C Step 4

D Step 5

💡 Hint

Look at the 'Worker Action' column to see when it changes from Idle to Processing job.

If the worker never runs, what happens to the Notification Status?

A It stays Queued

B It becomes Sending

C It becomes Completed

D It becomes Not sent

💡 Hint

Refer to the 'Notification Status' in variable_tracker after Step 3 and Step 4.

Concept Snapshot

Laravel queued notifications:
- Trigger notification event
- Notification instance created
- Job queued (not sent immediately)
- Worker processes job
- Notification sent via defined channel
- Job marked completed
Use queues to avoid delays in user requests.

Full Transcript

In Laravel, queued notifications work by first triggering a notification event. This creates a notification instance, which is then queued as a job instead of sending immediately. The queue holds the job until a worker process picks it up. The worker then sends the notification through the specified channel, such as email. After sending, the job is marked as completed and removed from the queue. This process helps keep user requests fast by handling notifications asynchronously.

Practice

1. What is the main benefit of using queued notifications in Laravel?

easy

A. They automatically retry failed notifications indefinitely.

B. They allow notifications to be sent only during business hours.

C. They send messages without slowing down your app.

D. They encrypt notification content for security.

Solution

1. Step 1: Understand queued notifications purpose

   Queued notifications delay sending to avoid blocking app processes.

2. Step 2: Identify the main benefit

   This means the app stays fast because sending happens in the background.

3. Final Answer:

   They send messages without slowing down your app. -> Option C

4. Quick Check:

   Queued notifications improve app speed = B [OK]

Hint: Queued notifications run in background to keep app fast [OK]

Common Mistakes:

• Thinking queued notifications encrypt messages
• Assuming they only send during specific hours
• Believing they retry indefinitely without limits

2. Which interface must a Laravel notification implement to be queued?

easy

A. QueueInterface

B. Queueable

C. ShouldNotify

D. ShouldQueue

Solution

1. Step 1: Recall Laravel notification queue setup

   Notifications must implement the ShouldQueue interface to be queued.

2. Step 2: Differentiate interface and trait

   Queueable is a trait to help with queue features, not an interface.

3. Final Answer:

   ShouldQueue -> Option D

4. Quick Check:

   Implement ShouldQueue to queue notifications = A [OK]

Hint: Implement ShouldQueue interface to queue notifications [OK]

Common Mistakes:

• Confusing Queueable trait with interface
• Using non-existent interfaces like ShouldNotify
• Assuming QueueInterface is required

3. Given this notification class snippet, what will happen when notify() is called?

use Illuminate\Notifications\Notification;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;

class InvoicePaid extends Notification implements ShouldQueue
{
    use Queueable;

    public function via($notifiable)
    {
        return ['mail'];
    }

    public function toMail($notifiable)
    {
        return (new MailMessage)->line('Invoice paid.');
    }
}

medium

A. The notification will be sent immediately without queuing.

B. The notification will be queued and sent asynchronously.

C. The notification will fail because Queueable trait is missing.

D. The notification will send via SMS instead of mail.

Solution

1. Step 1: Check if notification implements ShouldQueue

   The class implements ShouldQueue, so it will be queued.

2. Step 2: Confirm use of Queueable trait and mail channel

   Queueable trait is used, and via() returns 'mail', so mail will be sent asynchronously.

3. Final Answer:

   The notification will be queued and sent asynchronously. -> Option B

4. Quick Check:

   ShouldQueue + Queueable = queued notification = D [OK]

Hint: Implement ShouldQueue and use Queueable to queue notifications [OK]

Common Mistakes:

• Assuming Queueable trait is optional
• Thinking notification sends immediately despite ShouldQueue
• Confusing mail channel with SMS

4. What is wrong with this notification class if it does not queue as expected?

use Illuminate\Notifications\Notification;
use Illuminate\Bus\Queueable;

class OrderShipped extends Notification
{
    use Queueable;

    public function via($notifiable)
    {
        return ['mail'];
    }

    public function toMail($notifiable)
    {
        return (new MailMessage)->line('Order shipped.');
    }
}

medium

A. It is missing the ShouldQueue interface implementation.

B. The Queueable trait should not be used here.

C. The via() method must return 'database' to queue notifications.

D. The toMail() method must be named toQueuedMail() to queue.

Solution

1. Step 1: Check interface implementation for queuing

   The class uses Queueable trait but does not implement ShouldQueue interface.

2. Step 2: Understand queuing requirements

   Without ShouldQueue, Laravel sends notification immediately, ignoring queue.

3. Final Answer:

   It is missing the ShouldQueue interface implementation. -> Option A

4. Quick Check:

   Must implement ShouldQueue to queue notifications = A [OK]

Hint: Implement ShouldQueue interface to enable queuing [OK]

Common Mistakes:

• Thinking Queueable trait alone queues notifications
• Believing via() channel affects queuing
• Renaming toMail() method incorrectly

5. You want to send a notification that queues and retries up to 3 times if it fails. Which code snippet correctly sets this up? A)

class PaymentFailed extends Notification implements ShouldQueue
{
    use Queueable;

    public $tries = 3;

    public function via($notifiable) { return ['mail']; }
}

B)

class PaymentFailed extends Notification implements ShouldQueue
{
    use Queueable;

    public function via($notifiable) { return ['mail']; }

    public function retryTimes() { return 3; }
}

C)

class PaymentFailed extends Notification
{
    use Queueable;

    public $tries = 3;

    public function via($notifiable) { return ['mail']; }
}

D)

class PaymentFailed extends Notification implements ShouldQueue
{
    use Queueable;

    public function via($notifiable) { return ['mail']; }

    public $maxRetries = 3;
}

hard

A. Correctly sets retry attempts with public $tries property.

B. Uses retryTimes() method which Laravel does not recognize.

C. Missing ShouldQueue interface, so notification won't queue.

D. Uses $maxRetries property which is not used by Laravel.

Solution

1. Step 1: Identify queuing and retry setup

   Laravel uses public $tries property to set retry attempts on queued jobs/notifications.

2. Step 2: Check interface and property correctness

   Correctly sets retry attempts with public $tries property. implements ShouldQueue and sets public $tries = 3 correctly.

3. Final Answer:

   Correctly sets retry attempts with public $tries property. -> Option A

4. Quick Check:

   Use public $tries for retries in queued notifications = A [OK]

Hint: Set public $tries = 3 and implement ShouldQueue to retry [OK]

Common Mistakes:

• Using non-existent retryTimes() method
• Forgetting to implement ShouldQueue interface
• Using wrong property name like $maxRetries