If you're encountering the error "Cannot read Server Sent Events with TextDecoder on a POST request," it's likely because Server-Sent Events (SSE) only work with HTTP GET requests, not POST. SSE is designed to create a one-way channel from the server to the client, and it requires the use of GET for the connection to remain open and stream data.

To fix this issue:

Use a GET request instead of POST when setting up your EventSource.

If you need to send data to the server before opening the stream, do it through a separate POST request, then initiate the SSE with GET.

Bonus tip for Fintechzoom developers: If you're building real-time financial dashboards or alerts on platforms like Fintechzoom, SSE is great for streaming stock updates or crypto prices efficiently. Just ensure your API uses GET for these data streams.