Return JSON details of failed validation with Laravel 8

I’m creating an endpoint to store an Office with two fields: name, address. When validation fails laravel returns status 200 and a welcome page. It should return 4xx and error details with JSON, shouldn’t it? I tried to catch an exception (ValidationError) but I don’t get the error details.

    public function store(Request $request)
    {
        $request->validate([
            'name' => 'required',
            'address' => 'required'
        ]);
        // if validation failed, 4xx?

        // logic to create a model here
        return $office; // everything fine, 201 and object details
    }

I’m testing it with unit test and postman:

    public function testValidationFailed()
    {
        $payload = [
            "wrongfield" => "Example Name"
        ];

        $response = $this->postJson('/api/offices/', $payload);

and with postman the content-type is application/json

EDITED Postman was messing up the headers. httpie and curl get the correct response with this code and the accepted answer’s.

Answer

You can use Validator instead like so

$validator = Validator::make($request->all(), [
      'name' => 'required',
      'address' => 'required'
]);

if ($validator->fails()) {
   return response()->json($validator->errors(), 404);
}

Or you can use validator() helper method

validator($request->all(), [
    'name' => 'required',
    'address' => 'required'
])->validate();

This will automatically validate and response back with errors and it also, works with web and api endpoints.