I’m not sure, if I get the question right. You just want to write JSON data to a file using Boto3? The following code writes a python dictionary to a JSON file.
import json
import boto3
s3 = boto3.resource('s3')
s3object = s3.Object('your-bucket-name', 'your_file.json')
s3object.put(
Body=(bytes(json.dumps(json_data).encode('UTF-8')))
)