jsonify_encoder

app.py

def configure_json_encoder(app):
    from decimal import Decimal
    class CustomJsonEncoder(json.JSONEncoder):
        def default(self, obj):
            if isinstance(obj, Decimal):
                return str(obj)
            if obj is None:
                return str('')
            return super(CustomJsonEncoder, self).default(obj)

    app.json_encoder = CustomJsonEncoder