$ heroku plugins:install heroku-cli-api
$ heroku api [--version VERSION] METHOD PATH
The api command is a convenient but low-level way to send requests to the Heroku API. It sends an HTTP request to the Heroku API using the given method on the given path. For methods PUT, PATCH, and POST, it uses stdin unmodified as the request body. It prints the response unmodified on stdout.
Method name input will be upcased, so both 'heroku api GET /apps' and 'heroku api get /apps' are valid commands.
Examples:
$ heroku api GET /apps/myapp
{ created_at: "2011-11-11T04:17:13-00:00",
id: "12345678-9abc-def0-1234-456789012345",
name: "myapp",
…
}
$ heroku api -v 3.variant /apps
# Something different
$ export HEROKU_HEADERS
$ HEROKU_HEADERS='
Content-Type: application/x-www-form-urlencoded
Accept: application/json
'
$ printf 'type=web&qty=2' | heroku api POST /apps/myapp/ps/scale
2