Can someone explain to me in what language this API code is written in?

I am supposed to create an API using this code. However I am not sure what language this is written in.

 curl -v -X POST \
    -H "Accept: application/json" \
    -H "Content-Type: application/json" \
    -H "Authorization: SSWS ${api_token}" \
    -d '{
      "profile": {
        "firstName": "Isaac",
        "lastName": "Brock",
        "email": "isaac.brock@example.com",
        "login": "isaac.brock@example.com",
        "mobilePhone": "..."
      },
      "credentials": {
        "password" : { "value": "..." }
      }
    }' "https://${org}.okta.com/api/v1/users?activate=false"

You are currently doing a curl using a shell:

See what is a shell(bash for example):

https://fr.wikipedia.org/wiki/Bourne-Again_shell

You are sending data using POST request, and for sending this data you are using a JSON format file.

I think you will have to create a webservice that accept JSON input

https://fr.wikipedia.org/wiki/JavaScript_Object_Notation

Please be more specific in your question, if it is not what you want.