The curl command is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP).
$ sudo apt install curl
$ curl -X POST -H "Content-Type: application/json" -d '{"id": "1"}' localhost:3000/api/v1/users
$ curl -X PUT -H "Content-Type: application/json" -d '{"id": "1", "key": "value"}' localhost:3000/api/v1/users
$ curl -X POST -H "Content-Type: application/json" -d '{"id": "1"}' localhost:3000/api/v1/users
$ curl -X POST -H 'Accept: application/json' -H "Authorization: Bearer ${TOKEN}" -d '{"id": "1"}' localhost:3000/api/v1/users
$ curl --basic -u $username:$password https://api.example.com/api/sample.json -H "accept: application/json"