Inline validation — Validation

The shortest path is $request->validate() — it throws a ValidationException that Laravel catches and turns into a redirect-back with errors.

public function store(Request $request)
{
    $data = $request->validate([
        'title' => ['required', 'string', 'max:160'],
        'body'  => ['required'],
        'tags'  => ['nullable', 'array', 'max:5'],
        'tags.*'=> ['string', 'max:30'],
    ]);

    Post::create($data);

    return redirect()->route('posts.index')->with('success', 'Saved.');
}

$data contains only the keys you validated — safe to pass straight to create().

Rule arrays vs pipe strings

These are equivalent:

'email' => 'required|email|unique:users'
'email' => ['required', 'email', Rule::unique('users')]

Use the array form when a rule needs arguments (Rule::in([…]), Rule::unique('users')->ignore($id)).

Validation errors in Blade

@error('title') <p class="err">{{ $message }}</p> @enderror

Or check the bag: $errors->first('title').