<?php

$data = [
    'content/price/value' => 10.01,
    'content/price/currency' => 'USD',
    'content/shipping/free' => false,
    'content/descrtiption' => 'hallo meine name ist dominik stapf',
    'content/erp_name/0/locale' => 'en_US',
    'content/erp_name/0/scope' => null,
    'content/erp_name/0/data' => 'Jack',
    'content/erp_name/1/locale' => 'de_DE',
    'content/erp_name/1/scope' => 'NULL',
    'content/erp_name/1/data' => 'Jacke'
];

$result = [];

foreach ($data as $structure => $value) {
    $reference = &$result;

    $nodes = explode('/', $structure);

    foreach ($nodes as $node) {
        if (!isset($reference[$node])) {
            $reference[$node] = [];
        }
        $reference = &$reference[$node];
    }

    $reference = $value === 'NULL' ? null : $value;
}

echo json_encode($result, JSON_PRETTY_PRINT);