fffft | fft impl for ff : :Field

The reason you are getting the "garbled" data is that you are using request.get_data(). That method will return the raw data of a request, but not do any decoding for you.

Much more convenient is to use request.form.get('payload'), which will directly give you the JSON string of the request object. You can then convert that into a dict object with json.loads() to process it further in your app.

Note that the format you received is the correct format for interactive messages. You will not get a query string (e.g. "token=abc;user_id?def...") as you suggested (like for slash command requests). Interactive message request will always contain the request as JSON string in a payload form property. See here for reference.

Here is a simple working example, which will reply a greeting to the user that pressed the button. It will work directly with Slack, but I recommend using Postman to test it.