I use jq to pretty-print it.
jq is a lightweight and flexible command-line JSON processor.
jq is written in portable C, and it has zero runtime dependencies.
E.g.
Without JSON formatter
$ curl -s http://localhost:3000; echo
{"account":{"id":"HXRC","uri":["mailto:Lizzie.Koepp@hotmail.com","tel:366-643-7219"],"features":["585"],"nickname":"Consultant"}}
Install jq(Ubuntu):
$ sudo apt-get install jq
Use jq json formatter.
$ curl -s http://localhost:3000 | jq '.'
{
  "account": {
    "id": "HXRC",
    "uri": [
      "mailto:Lizzie.Koepp@hotmail.com",
      "tel:366-643-7219"
    ],
    "features": [
      "585"
    ],
    "nickname": "Consultant"
  }
}
You can find more examples in tutorial. You can find the installation for each OS in download page