How do I properly send a POST request in curl? or What’s the correct way to make a POST request in cu

Been there! For a post request in curl, the `-d` flag is right, but some APIs need `--data-raw` or `--data-binary` instead.

Also, if the server gives a vague error, try `-i` to see response headers. Might hint at what’s missing.

Example:
```
curl -X POST https://example.com/api \
-H "Content-Type: application/json" \
-d '{"key":"value"}' -i
```