For JSON data, you gotta escape the quotes properly in some shells. Try:
```
curl -X POST https://example.com/api \
-H "Content-Type: application/json" \
-d "{\"key\":\"value\"}"
```
Or just use a file with `-d @data.json`. Way cleaner!
```
curl -X POST https://example.com/api \
-H "Content-Type: application/json" \
-d "{\"key\":\"value\"}"
```
Or just use a file with `-d @data.json`. Way cleaner!
