Yes, this is possible. Build your JSON output as a string in PowerApps. Make sure you use single quotes rather than double quotes. Then send that string to Flow as a Parameter. In Flow you can use a sample of your JSON output to create the schema in a Parse Json action. Feed the JSON string you get as input into that action and you will have dynamic content for the fields in the JSON output. For example I built a test using the followin JSON
{
'employee': {
'name': 'LastName',
'salary': 56000,
'married': true
}
}
I passed that as a string to Flow from a PowerApps button. Then Parsed it in Flow. AFter that was done I had access to name, salary, and married as dynamic content in Flow.
The one limitation is that you have to use a fixed JSON schema so that Flow will know how to read the string you pass.
