Octet-Stream JSON Extraction

I’m working with an API where the data used to be exchanged as JSON, so I already know the structure of the payload. Recently, however, the same endpoint started returning data as application/octet-stream instead.

What I need help with is understanding how to correctly handle this change: how to inspect what the request body is actually sending, and how the response should be interpreted or decoded so the system continues to work properly.

All required data is already available on my side. The main challenge is figuring out how the octet-stream format is constructed and how to send and receive it in the way the API expects, instead of plain JSON.

I’m looking for a small, clear solution (Node.js or Python is fine) that can capture the exact request (URL, headers, body), read the corresponding octet-stream response, and reveal the underlying data format so it can be converted back into usable JSON for my existing code.