The output is correct. $customers{'cust'} contains a (reference to a) hash with the keys "id" and "name". The encode_json output shows precisely that.

So if you want your result to be a map containing an array containing a map, you'd have to alter your original data structure to represent that. Instead of having $customers{'cust'} contain a hashref, have it contain an arrayref instead.

# I didn't test the code, but I suspect this should give you what you 
+want.
$customers{'cust'} = [
    {
        id => $id,
        name => $name,
    }
];
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