Laravel Observers Explained: From Clean CRUD Hooks to Production-Grade Event Architecture

What Is an Observer in Laravel?

In Laravel, an Observer is a class that listens to Eloquent model lifecycle events and encapsulates side effects away from controllers and models.

Instead of this:

public function store(Request $request)
{
   $user = User::create($request->all());
   Mail::to($user->email)->send(new WelcomeMail($user));
}

You move the side effect into an observer tied to the model.

Eloquent Model Events (The Trigger Points)

Laravel fires these events automatically:

• retrieved

• creating / created

• updating / updated

• saving / saved

• deleting / deleted

• restoring / restored

• forceDeleted

Rule of thumb:

• Use creating / updating to mutate attributes.

• Use created / updated for side effects (notifications, logs, jobs).

Basic Implementation

1. Create Observer

php artisan make:observer UserObserver --model=User

This generates:

class UserObserver
{
    public function created(User $user)
    {
        //
    }
}

2. Register the Observer

In AppServiceProvider:

use App\Models\User;
use App\Observers\UserObserver;

public function boot()
{
    User::observe(UserObserver::class);
}

3. Real-World Example: Auto-Generate Slug

public function creating(Post $post)
{
    $post->slug = Str::slug($post->title);
}

Why creating?
Because it runs before insert, allowing attribute mutation.

Practical Use Cases (That Actually Matter)

1. Audit Logging (Production-Grade SaaS)

public function updated(Order $order)
{
    ActivityLog::create([
        'model' => Order::class,
        'model_id' => $order->id,
        'changes' => json_encode($order->getChanges()),
    ]);
}

Use case:

• Financial platforms

• Compliance-heavy SaaS

• Enterprise dashboards

2. Dispatch Jobs Instead of Doing Heavy Work

Never send emails directly in observers.

Bad:

Mail::to($user)->send(new WelcomeMail($user));

Correct:

public function created(User $user)
{
    SendWelcomeEmail::dispatch($user);
}

This keeps request lifecycle fast and scalable.

3. Enforcing Business Rules

Prevent deletion if dependent data exists:

public function deleting(Project $project)
{
    if ($project->tasks()->exists()) {
        throw new \Exception("Cannot delete project with tasks.");
    }
}

Now the rule is centralized, not scattered across controllers.

Advanced Patterns

1. Observer + Domain Events (Clean Architecture)

Instead of putting logic directly in the observer:

public function created(User $user)
{
    event(new UserRegistered($user));
}

This keeps observers thin and moves business logic into listeners.

2. Prevent Infinite Loops

If you update a model inside updated, you can trigger recursion.

Bad:

public function updated(User $user)
{
    $user->update(['synced' => true]);
}

Fix:

$user->updateQuietly(['synced' => true]);

Or:

User::withoutEvents(function () use ($user) {
    $user->update(['synced' => true]);
});

3. Handling Soft Deletes

If using SoftDeletes:

• deleting runs

• deleted runs

• forceDeleted runs only on permanent delete

Design logic accordingly.

4. Queue Observers Globally (High-Scale Apps)

Instead of dispatching jobs manually:

class UserObserver implements ShouldQueue

Now observer logic is queued automatically.

This is powerful in:

• High-traffic SaaS

• Marketplace platforms

• Payment systems

5. Observers in Multi-Tenant Apps

Inject tenant context before persistence:

public function creating(Model $model)
{
    $model->tenant_id = tenant()->id;
}

This guarantees tenant isolation at persistence level.

Performance Considerations

Observers run automatically on every model lifecycle event.

Be careful when:

• Bulk importing data

• Running seeders

• Running migrations

• Executing batch updates

Disable when needed:

Model::withoutEvents(function () {
    User::insert($bulkData);
});

Observers vs Model Events vs Global Scopes

Do not use observers for:

• Authorization

• Validation

• HTTP-level decisions

Anti-Patterns (Avoid These)

1. Business logic explosion inside observers

2. Sending emails synchronously

3. Hidden side effects developers cannot trace

4. Mutating unrelated models silently

Observers should be:

• Deterministic

• Lightweight

• Transparent

Real SaaS Example Architecture

Imagine a subscription platform:

When Subscription is created:

Observer:

public function created(Subscription $subscription)
{
    SyncWithStripe::dispatch($subscription);
    GenerateInvoice::dispatch($subscription);
    NotifyAdmin::dispatch($subscription);
}

Now:

• Controllers stay clean

• Business rules centralized

• Side effects scalable

Testing Observers Properly

Use:

Event::fake();
Queue::fake();

Or test observer behavior directly:

$user = User::factory()->create();
$this->assertDatabaseHas('activity_logs', [
    'model_id' => $user->id,
]);

When NOT to Use Observers

Do not use them when:

• Logic depends on HTTP request context

• You need explicit control over execution order

• The logic is domain-specific and not model-lifecycle specific

In complex systems, domain events may be cleaner.

Strategic Guidance for Founders & CTOs

Observers are valuable when:

• You want clean controllers

• You want automatic system behaviors

• You need centralized persistence rules

But in large-scale SaaS:

• Combine Observers with Domain Events

• Avoid heavy synchronous processing

• Document side effects clearly

Final Takeaway

Observers are not just “nice Laravel features.”
They are persistence-layer automation tools.

Used properly:

• They reduce duplication

• They centralize rules

• They enforce data integrity

Used poorly:

• They create hidden chaos

Architect them deliberately.