Home Assistant RESTful command

Use a rest_command in configuration.yaml:

rest_command:
  openapp_cars_gate:
    url: "https://openapp.house/api/v1/entities/ENTITY_ID/actions/switchable.open"
    method: POST
    headers:
      X-API-Key: "https://openapp.house_openapp_YOUR_SECRET"
      Content-Type: "application/json"
    payload: "{}"

Trigger from an automation or script:

service: rest_command.openapp_cars_gate

Create the API key from the dashboard Voice control wizard (one entity, finite expiry).