curl --request GET \
  --url https://api.otark.energy/v1/transactions/{transaction_id}/history \
  --header 'X-Api-Key: <api-key>'

{
  "transactions": [
    {
      "id": "txn_k8m2p4q7r1",
      "type": "ppa",
      "contract_id": "con_a1b2c3d4",
      "status": "valid",
      "version": 2,
      "sender": {
        "eic": "11YWINDPARKNO--A",
        "asset": {
          "id": "ast_w1x2y3z4",
          "name": "Zonnepark De Wilgen",
          "nominal_power": 25,
          "technology": "solar",
          "tso": "TenneT"
        },
        "tso": "TenneT"
      },
      "receiver": {
        "eic": "11YGREENENERGY-Z",
        "tso": "TenneT"
      },
      "delivery_start": "2026-01-15T14:00:00Z",
      "delivery_end": "2026-01-15T14:15:00Z",
      "slot_number": 57,
      "volume": 12.5,
      "created_at": "2026-01-14T18:00:00Z",
      "previous_transaction_id": "txn_j5n3w8v2x6"
    }
  ]
}