curl "https://app.ranked.ai/api/v1/projects/{projectId}/backlinks/history" \
  -H "Authorization: Bearer rk_live_your_api_key"

{
  "success": true,
  "data": {
    "history": [
      {
        "check_date": "2026-05-01",
        "new_backlinks": 3,
        "lost_backlinks": 1,
        "new_referring_domains": 2,
        "lost_referring_domains": 0,
        "net_backlinks_change": 2,
        "net_domains_change": 2
      },
      {
        "check_date": "2026-04-24",
        "new_backlinks": 5,
        "lost_backlinks": 0,
        "new_referring_domains": 4,
        "lost_referring_domains": 1,
        "net_backlinks_change": 5,
        "net_domains_change": 3
      }
    ],
    "summary": {
      "total_new": 8,
      "total_lost": 1,
      "net_change": 7
    }
  }
}