Is it possible for you to store that number as an integer instead, for example
apiData.run_id = int64(1720787);
?
Because then
apiData = struct;
apiData.run_id = int64(1720787);
apiData.run = "BSCR_sbt rerun: PT Jan01_2023";
apiData.run_node_ids = [20970];
apiData.scale_load_factor = 1000.1;
if length( apiData.run_node_ids)== 1
apiData.run_node_ids = { apiData.run_node_ids};
end
jsonInp = string( jsonencode( apiData, 'PrettyPrint', true))