Using cURL for API Requests

Motivation

When building APIs, you need a way to send requests to test out what you are building. For big projects, tools like Postman or Insomnia are a great choice because they offer much more than just a way to send requests.

However, for small projects where all you need is a way to send requests to test your API, I find using cURL much more convenient. Not only that, but you also look cool, and who doesn't want that.

Sending requests

GET and DELETE

If not specified differently, default HTTP method is GET.

curl [url]

curl http://localhost:8000/api/v1/todos

To specify different HTTP methid use the -X option.

curl -X DELETE [url]

curl -X DELETE http://localhost:8000/api/v1/todos/1

POST, PUT and PATCH

For sending requests with data, use -d flag.

curl -X POST -d @data.json http://localhost:8000/api/v1/todos 

curl -X PUT -d @data.json http://localhost:8000/api/v1/todos 

curl -X PATCH -d @data.json http://localhost:8000/api/v1/todos 

{  "title": "foo",  "body": "bar",  "userId": 1 } 

If you are using -d flag, request is by default treated as POST request, so you can omit the -X option.

curl -d @data.json http://localhost:8000/api/v1/todos 

Other useful configuration

Query parameters

When using query parameters, wrap the url in "" to avoid potential problems.

curl "http://localhost:8000/api/v1/todos?id=1" 

Sending headers

To send request headers use -H option.

curl -H "Authorization: Bearer <token>" http://localhost:8000/api/v1/todos 

Reading response status and headers

To see information such as response status and response headers, use -i flag.

curl -i http://localhost:8000/api/v1/todos 

When things get messy

When you need to send a request with multiple headers and a long url, it can quickly become a burden to type everything. You can easily end up with something like this:

curl -i -X POST -H "Content-Type: application/json" -H "Authorization: Bearer <token>" -d @data.json http://localhost:8000/api/v1/todos 

To avoid that, I recommend using a cli tool like endpoint.