For post in curl, headers are everything. Some APIs need `Accept: application/json` alongside `Content-Type`. Also, escape quotes if your shell freaks out:
```bash
curl -X POST https://example.com/api -H "Content-Type: application/json" -H "Accept: application/json" -d "{\"key\":\"value\"}"
```
If it still fails, share the error—might be a server-side thing.
```bash
curl -X POST https://example.com/api -H "Content-Type: application/json" -H "Accept: application/json" -d "{\"key\":\"value\"}"
```
If it still fails, share the error—might be a server-side thing.
