How to set up downlink msg process in AWS Web services

Hi Everyone!, We have integrated a few IoT devices on LoRa WAN network (TTN), with AWS IoT services. So data sent by devices are ending up nicely in a database within AWS. Now trying to create a user interface for devices so they can be controlled or reset via downlink msg.

As far as I can see the downlink process in AWS is via “Shadow Device” and MQTT, but I need to invoke this process by coding I assume in Python or Java in a web-based application so that I can send the downlink data.

Which web-services or web development module in AWS is suitable for this user interface to control IOT devices?