curl --request GET \
  --url https://api.lmnt.com/v1/account \
  --header 'X-API-Key: <api-key>'

{
  "plan": {
    "character_limit": 123,
    "commercial_use_allowed": true,
    "instant_voice_limit": 123,
    "professional_voice_limit": 123,
    "type": "<string>"
  },
  "usage": {
    "characters": 123,
    "instant_voices": 123,
    "professional_voices": 123
  }
}