Newbie - php api data formatting?

Hey guys, around 10-12 years ago I designed in PHP however a lot has happened and now I’m looking at connecting to the API on Monday.

I’m using the standard

$query = '
query {
boards (ids: 0000xxxxxx00000) {
groups (ids: group_title) {
    items {
      id
      name
      column_values {
        id
        text
        title
      }
    }
  }
}
}
';

$data = @file_get_contents($apiUrl, false, stream_context_create([
 'http' => [
  'method' => 'POST',
  'header' => $headers,
  'content' => json_encode(['query' => $query]),
 ]
]));
$responseContent = json_decode($data, true);

echo json_encode($responseContent);

and its pulling all the data out but with no formatting at all - Can you point me in the right direction how to add
tags etc after each line etc etc…

Thanks in advance