Laravel Validation Rules Reference Guide

Validating in a controller

public function store(Request $request)
{
    $validated = $request->validate([
        'title' => 'required|string|max:255',
        'email' => 'required|email|unique:users,email',
        'age' => 'nullable|integer|min:18',
    ]);

    Post::create($validated);
}

If validation fails, Laravel automatically redirects back with the errors flashed to the session (for a web request) or returns a 422 JSON response with the error details (for an API request) — nothing else to write.

Common rules

Rule	Checks
required	Present and not empty.
nullable	Allows the field to be missing or null — skips other rules when it is.
sometimes	Only validates the field when it's actually present in the input.
string / integer / numeric / boolean / array	Must be that PHP type.
email	Must be a validly formatted email address.
unique:users,email	No existing row in users.email matches this value.
exists:users,id	A row with this value must already exist in users.id.
min:8 / max:255	Minimum/maximum length (strings), value (numbers), or item count (arrays).
between:1,100	Value or length falls within the given range.
confirmed	A matching {field}_confirmation field must be present (e.g. password confirmation).
date / date_format:Y-m-d	Must be a valid date, optionally in a specific format.
in:draft,published,archived	Value must be one of the given options.
regex:/^[A-Z]+$/	Must match the given regular expression.
file / image / mimes:jpg,png,pdf	Uploaded file constraints, including allowed MIME types.
required_if:type,business	Required only when another field has a given value.
same:password / different:old_password	Must (or must not) match another field's value.

Custom error messages

$request->validate([
    'title' => 'required|max:255',
], [
    'title.required' => 'Please give your post a title.',
    'title.max' => 'Titles cannot be longer than 255 characters.',
]);

Form Requests

For anything beyond a couple of rules, move validation into its own class so the controller stays focused on the actual logic.

php artisan make:request StorePostRequest

class StorePostRequest extends FormRequest
{
    public function authorize(): bool
    {
        return true;
    }

    public function rules(): array
    {
        return [
            'title' => ['required', 'string', 'max:255'],
            'body' => ['required', 'string'],
        ];
    }

    public function messages(): array
    {
        return [
            'title.required' => 'Please give your post a title.',
        ];
    }
}

public function store(StorePostRequest $request)
{
    // Already validated by the time this method runs
    Post::create($request->validated());
}

Manual validator instances

Useful outside of a controller/request, e.g. validating an array in a job or console command.

use Illuminate\Support\Facades\Validator;

$validator = Validator::make($data, [
    'email' => 'required|email',
]);

if ($validator->fails()) {
    return redirect()->back()->withErrors($validator)->withInput();
}