{
  "symbol": "EURCHF",
  "display": "EURCHF",
  "asset_class": "forex",
  "timeframe": "M30",
  "rows": 6494,
  "start": "2025.06.18 14:00:00",
  "end": "2025.12.24 21:30:00",
  "score": 80.0,
  "grade": "B",
  "critical_count": 0,
  "warning_count": 2,
  "checks": {
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    "out_of_order": 0,
    "ohlc_violations": 0,
    "nonpositive_prices": 0,
    "flat_bars": 0,
    "flat_bars_pct": 0.0,
    "zero_volume": 6494,
    "zero_volume_pct": 100.0,
    "zero_spread": 6494,
    "zero_spread_pct": 100.0,
    "negative_spread": 0,
    "extreme_returns": 0,
    "gaps": 0,
    "largest_gap_seconds": 0,
    "largest_gap_start": "",
    "weekend_bars": 0
  },
  "issues": [
    {
      "severity": "warning",
      "check": "zero_volume",
      "count": 6494,
      "message": "Zero or missing tick volume"
    },
    {
      "severity": "warning",
      "check": "zero_spread",
      "count": 6494,
      "message": "Zero or missing spread"
    }
  ],
  "generated_at": "2026-11-01",
  "report_url": "/historical-data/data-quality/detail.php?symbol=EURCHF&tf=M30"
}