curl --request GET \
  --url http://localhost:3000/billing/usage \
  --header 'Authorization: Bearer <token>'

{
  "apiCalls": {
    "used": 123,
    "limit": 123
  },
  "flags": {
    "used": 123,
    "limit": 123
  },
  "projects": {
    "used": 123,
    "limit": 123
  }
}