curl --request GET \
  --url https://{subdomain}.nudj.cx/api/v2/analytics/challenges/stats/overview

{
  "summary": {
    "totalParticipants": 123,
    "totalCompletions": 123,
    "completionRate": 123,
    "averageTimeToCompleteHours": 123,
    "startedNotCompleted": 123
  },
  "actionsBreakdown": [
    {
      "actionId": "<string>",
      "actionTitle": "<string>",
      "totalCompletions": 123,
      "completionRate": 123
    }
  ],
  "participantsByDay": [
    {
      "date": "<string>",
      "count": 123
    }
  ],
  "timeseries": [
    {
      "date": "<string>",
      "started": 123,
      "completed": 123,
      "uniqueUsers": 123
    }
  ],
  "funnel": [
    {
      "step": "<string>",
      "users": 123,
      "conversionFromStart": 123
    }
  ]
}