Put/Call Ratio API

A put/call ratio is only meaningful after the measurement boundary is defined. A ticker-level daily ratio, a single-expiration intraday ratio, and a market-wide open-interest ratio are different statistics. They can all be useful, but they should not be compared as if they were the same variable.

For scanner work, start with contract volume inside a controlled expiration window, then add open interest and spread filters. Volume tells you what traded in the current session. Open interest tells you how much exposure was standing after the previous reporting cycle. Spread and quote checks tell you whether the contracts were liquid enough for a signal to matter.

def put_call_ratio(chain_results):
    call_volume = 0
    put_volume = 0
    call_oi = 0
    put_oi = 0

    for contract in chain_results:
        details = contract.get("details", {})
        contract_type = details.get("contract_type")
        volume = contract.get("day", {}).get("volume") or 0
        open_interest = contract.get("open_interest") or 0

        if contract_type == "call":
            call_volume += volume
            call_oi += open_interest
        elif contract_type == "put":
            put_volume += volume
            put_oi += open_interest

    return {
        "volume_ratio": put_volume / call_volume if call_volume else None,
        "open_interest_ratio": put_oi / call_oi if call_oi else None,
    }