Basic cURL HTTP commands

01 October, 2020

cURL is versatile URL request tool that is vastly used among web developers, everyone should know at least basics. If you have any problems with endpoint provided by backend it is best to provide in bug ticket cURL request that is failing. You don't argue with cURL.

GET

curl 'https://example.com/posts/1'

GET with header

Note \ at the end of the first line, it is new line brake character.

curl --header 'accept: application/json, text/plain, */*' \
      'https://example.com/posts/1'

GET with params

curl 'https://example.com/posts?userId=1'

POST with header and JSON data

    curl --header "Content-Type:application/json" \
         --data "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":\"1\"}" \
          'https://example.com/posts'

The most common mistake in this type of query is forcing cURL to change request type by -X POST or --request POST. cURL don't need this for POST, it will invoke POST method thanks to --data parameter.

JSON placed in --data parameter must be stringified. There are a lot of tools to stringify JSON online, like JSON Stringify Online Tool.

POST with form data (multipart)

curl  -F firstName=john \
      -F lastName=doe \
      -F cv=@pathToFile.pdf 'http://example.com/submit'

PUT with header and JSON data

curl --request PUT \
     --data "{\"title\":\"foo\",\"body\":\"bar\",\"userId\":\"1\"}" \
     --header "Content-Type:application/json" \
      'https://example.com/posts/1'

Now -X PUT or --request PUT is expected. POST, PUT and PATCH are similar, cURL must know which request type we would like to perform.

PATCH with header and JSON data

curl --request PATCH \
     --header "Content-Type:application/json" \
     --data "{\"title\":\"foo\"}" \
      'https://example.com/posts/1'

DELETE

curl --request DELETE \
      'https://example.com/posts/1'

Useful options

Include response headers and status code in the output

Most likely you would like to get response header and response code, then add --include or short -i option with your request.

curl 'https://example.com/posts/1' -i

Include verbose data with transmission details and request headers

Add --verbose or -v.

curl 'https://example.com/posts/1' -v