How to fix "Undefined variable" error in Laravel?

Solution

This can happen when a variable used in the Blade template has not been properly passed from the controller. Try the following:

1. Ensure the Variable is Passed from Controller

Check that the variable is included when returning the view:

return view('welcome', ['name' => $name]);

If using compact():

return view('welcome', compact('name'));

2. Use @isset or @empty in Blade Templates

If the variable might be missing, use Blade directives to prevent errors:

@isset($name)
    <p>Hello, </p>
@endisset

Or:

@empty($name)
    <p>No name provided.</p>
@endempty

3. Check Route Controller for Missing Data

Ensure the controller function responsible for rendering the view is correctly passing the expected variables.

4. Check Middleware and Session Variables

If you’re using session data, ensure the variable is set before accessing it:

session(['user' => 'John Doe']);

Then retrieve it in Blade:

{ { session('user') } }

To debug session values, use:

dd(session()->all());

5. Use Default Values in Blade Templates

To prevent errors, assign a default value:

<p>Hello, </p>

This ensures that even if $name is undefined, the template will not break.

By following these steps, you should be able to resolve the “Undefined variable” error in Laravel.