playback application using AWS connect

You may want to explore Chime SDK. Amazon Connect does not provide conference control capabilities. It is focused on the contact center aspect of an agent conference.

I re-read your question from a new perspective, but I still do not understand the WHY. I can provide a few recommendations, but I would really need to understand what you are trying to achieve from a user experience perspective. For #1 (Customers will dial into the Omni channel and input a conference ID) - this is a simple flow, it is all doable. For #2 (The call needs to remain active but won't be connected to an agent) - this is also a simple customer queue flow, a transfer to a queue that is not staffed. The longer this call stays in queue, the more you pay for it. For #3a (A web application where you can manage a playlist of audio URLs to play during the call) - you can use dynamic values for S3 prompts in the customer queue flow, with a poll logic implemented via Lambda. The Web app sets the next audio to play, on the next poll the flow will execute the play prompt audio you set via Web app. For #3b (Additionally, you need controls to manage the audio playback and disconnect the call) you can use the the Stop contact API to disconnect the call. (https://docs.aws.amazon.com/connect/latest/APIReference/API_StopContact.html). You will need to store the contact Id in a backend storage such as Dynamo DB (DDB), so your web app has access to the Key it needs to disconnect the contact. For #4 (The backend should capture user actions from the web application and execute corresponding actions on the AWS Connect call) - I assume you refer to changing the audio and the disconnect commands. This is not Connect specific, depending on how your Web app decides to update these audio file links or send the command, this can be implemented with serverless code. Your web app should handle this. So you have to: 1/ Create a simple flow that collects Conference ID and stores it in a DDB along with the call contact ID, then transfer the call to an unstaffed queue. 2/ and 3a/ Create a simple customer queue flow that plays a dynamic S3 prompt link file, and periodically polls to see what file it should play next. The S3 file link must be updated by your web app in a DDB, and the flow invokes a Lambda that reads this. The play prompt will use the value returned by Lambda ensuring your web app UI change is executed. 3b/ and 4/ For a well architected solution, you can separate your UI layer from a backend AWS layer that manages the communication with your web app UI, and performs the call disconnect and update file prompts.