List leagues, optionally filtered by sport + country

Example response

{
  "meta": {
    "date_window": {
      "timezone": "UTC",
      "start_utc": "2026-09-13T00:00:00.000Z",
      "end_utc": "2026-09-14T00:00:00.000Z"
    },
    "source": "official-league",
    "confidence": 0.95,
    "cache_age_ms": 4200,
    "request_id": "req_abc123",
    "note": "match_id is omitted on 380 of 380 rows in this response. The live feed behind them does not carry an id we can resolve to a stored match, so we return no id rather than one that will not work. For rows with ids you can call back into, use /v1/stored/matches with the same sport or league, for example /v1/stored/matches?league=epl."
  },
  "error": {
    "code": "NOT_FOUND"
  }
}