How To Send Array Of Objects Within Request Body In JSON Format Via Postman?

I want to test my API function by sending array of objects via postman When I send my request in JSON format to the function and then looping through the array to access each object property it gives me the following error: https://i.imgur.com/QV9MDsm.jpg

Here is my request: https://i.imgur.com/4584wf3.jpg

I searched how to send an array of objects using postman and found that I am doing it the right way I selected row under body section so I can add my request body and selected it's format as JSON and added "Content-Type: application/json" to the request header

My API function:

public function createRetailer(Request $request){
    $machines = $request->machineInfo;

    foreach($machines as $machine){
        $newMachine = new Machine;
        $newMachine->machine_no = $machine->machineNo;
        $newMachine->account_type = $machine->accountType;
        $newMachine->machine_type = $machine->machineType;
        $newMachine->retialer_id = $retailer->retailerId;
        $newMachine->save();
    }
}

I expect that i can access each array object properties as a PHP object but I found that it is not an object by testing it using is_object() function:

public function createRetailer(Request $request){
    $machines = $request->machineInfo;

    foreach($machines as $machine){
        return response()->json(is_object($machine));
    }
}

I do not know if the problem is within my request or something that I might misunderstand while retrieving data of the request in my controller function

Either it is an array and in that case, you can call

$object = (object) $machine;

Or it is a string aka JSON, you can call

$object = json_decode($machine);

Or if it is an object/array use

$machine['machineType'];

Also please add a dump of the $machine var

EDIT

Try sending the request not using [] because they will be converted into an array with objects in it, instead, if you remove the [] and only have {} it should only be one object in the request

"machineInfo" : {
    "machineNo" : "1123213",
    "accountType" : "Paid",
    //...rest here..
}

Try this:

 public function createRetailer(Request $request){
    $machines = $request->machineInfo;

    foreach($machines as $machine){
        $object = (object) $machine;
        return response()->json(is_object($object));
    }
}