How to test APIs with curl — Basic

Misc / Other API testing & debugging

Quick command-line checks without a GUI—useful in terminals, CI, and remote servers.

Learn: curl is ideal for scripts, documentation, and quick smoke tests. Pair with jq or a JSON formatter when responses are large.

Supplementary examples

PUT with JSON body

curl -s -X PUT http://localhost:5001/users/1 \
  -H "Content-Type: application/json" \
  -d '{"username":"updated"}'

Course example

curl -s http://localhost:5001/health

curl -s -X POST http://localhost:5001/users \
  -H "Content-Type: application/json" \
  -d '{"username":"demo"}'

Additional references & examples

curl manual
Command-line HTTP client for quick API checks.
HTTP status codes (MDN)
When to use 200, 201, 204, 400, 404, 500, and related codes.