I use textmagic.com to send SMS messages and whilst I could send messages easily enough using curl from the cli, I struggled a bit to get restful notifications working in HA. Here therefore is my config, more for my own records than anything else:
configuration:
notify:
- name: textmagic
platform: rest
resource: "https://rest.textmagic.com/api/v2/messages"
method : POST_JSON
data_template:
text: "{{ message }}"
phones: "{{ target }}"
headers:
X-TM-Username: !secret tmuser
X-TM-Key: !secret tmkey
Node-red notification:
{
"message": "testing 123",
"target": "44XXXXXXXXXX",
}