I had a similar problem, I needed to flatten a JSON payload so that it could be consumed by a bubble API workflow endpoint.
I started by looking at online tools.
I found this - https://konklone.io/json/
Essentially, it flattens the JSON into CSV and worked pretty well with nested JSON’s. Obviously, this is good as a one time, but cannot scale for a process.
I then tried using Zapier with Google Sheets. Use a “Zap” to flatten the incoming JSON, update each line as a separate Google Sheet row. Use another “Zap” to send this update to my bubble endpoint.
It worked - sort of. I was having issues with how Zapier was defining the JSON keys. More importantly, this implementation was not clean. I was basically using Google Sheets as a temporary database.
In the end, I chanced upon - https://flow.built.io/login. It is integration platform, with drag and drop capabilities to define your flow. They have “code blocks” called “activities” with which you can build your flow. For example, they have an activity called “JSON to CSV” and another called “HTTPS Request”. Combining these two did the trick for me. Also, in the long term, I think it is easily configurable and scalable.
Of course, it means learning yet another platform. It took me a couple of weeks to figure it out, but their customer support (through live chat) is amazing. For my use case this was a good fit.