Your First API Call

curl is the command-line way to talk HTTP. If you learn one API tool, make it this one — it's on every system and shows you exactly what's happening.

The simplest call

curl http://127.0.0.1:8471/items

Check (verified):

[{"id": 1, "name": "Widget"}, {"id": 2, "name": "Gadget"}]

That's a GET to /items — curl defaults to GET, prints the response body, and exits. (Run the test server from Building an API to follow along, or substitute any real API URL.)

Dissecting a POST

curl -X POST \
  -H "Content-Type: application/json" \
  -d '{"name": "Sprocket"}' \
  http://127.0.0.1:8471/items

Piece	Meaning
-X POST	Use the POST method (default is GET)
-H "Content-Type: application/json"	Header: "my body is JSON"
-d '{"name": "Sprocket"}'	The body — -d implies POST, but -X is explicit
The URL	Where it's going

Check (verified):

{"id": 3, "name": "Sprocket"}

And the status (curl hides it by default — ask):

curl -s -w "\nHTTP %{http_code}\n" -X POST \
  -H "Content-Type: application/json" \
  -d '{"name": "Sprocket"}' \
  http://127.0.0.1:8471/items

Check (verified):

{"id": 4, "name": "Sprocket"}
HTTP 201

201 Created — the REST convention for "made it." (The id increments because the server remembers — each run starts fresh.)

Quoting: single quotes save you

curl -d '{"name": "Sprocket"}' ...   # single quotes outside: safe
curl -d "{\"name\": \"Sprocket\"}" ... # double quotes: escape hell

JSON needs double quotes inside; the shell eats double quotes. So wrap the whole body in single quotes — the shell passes it through untouched. Same instinct as regex's raw strings.

DELETE and the quiet success

curl -s -w "\nHTTP %{http_code}\n" -X DELETE http://127.0.0.1:8471/items/4

Check (verified):

HTTP 204

No body — 204 No Content means "done, nothing to say." An empty response to a DELETE is success, not failure.

Next: Query Params and Headers