Retrieves a live combo by combo_id: legs, combo state, state_timestamp, creation_timestamp, and instrument_id. This is not the full instrument spec — use public/get_instrument with the same ID for tick size, commissions, and book state.

Looks up the live combo table only. Unknown IDs fail with combo not found; malformed IDs fail with wrong format. Expired or archivized combos that public/get_combo_ids no longer lists can still be loaded as instruments via public/get_instrument.

Use public/get_combo_ids to list live combo IDs.

📖 Related Article: Options Data Collection Best Practices

Try in API console

{
  "result": {
    "id": "BTC-FS-31DEC21-PERP",
    "state_timestamp": 1536569522277,
    "creation_timestamp": 1536569522277,
    "legs": [
      {
        "instrument_name": "BTC-PERPETUAL",
        "amount": -1
      }
    ]
  }
}