[Malleys]

Проверил на

PHP index.php"

<?php

$specs = json_decode($_POST['specs'], true);
print_r($specs);
var_dump($specs);

?>

в браузере запускаю

fetch("index.php", {
	method: "post",
	body: new URLSearchParams({
		specs: JSON.stringify([{name: "1", spec: "111"}, {name: "111", spec: "111"}, {name: "111", spec: "111111"}]),
	})
})
.then(response => response.text())
.then(console.log)

Всё работает, в консоли пишет

Array
(
    [0] => Array
        (
            [name] => 1
            [spec] => 111
        )

    [1] => Array
        (
            [name] => 111
            [spec] => 111
        )

    [2] => Array
        (
            [name] => 111
            [spec] => 111111
        )

)
array(3) {
  [0]=>
  array(2) {
    ["name"]=>
    string(1) "1"
    ["spec"]=>
    string(3) "111"
  }
  [1]=>
  array(2) {
    ["name"]=>
    string(3) "111"
    ["spec"]=>
    string(3) "111"
  }
  [2]=>
  array(2) {
    ["name"]=>
    string(3) "111"
    ["spec"]=>
    string(6) "111111"
  }
}