skew_25d = iv_put_25d - iv_call_25d (positive = downside protection priced over upside). The raw call_iv_skew/put_iv_skew strike rows of /iv-surface are the strike-space INPUT view; this endpoint answers in the delta convention practitioners quote. Contracts failing the shared IV plausibility gate or missing a delta are excluded and counted - the literal-0.0 IV marker never enters the formula. A target outside the reliable chain's delta range yields null, never an extrapolated number. Defaults to the nearest expiry; error codes match /snapshot.curl --location 'https://sugra.ai/api/v1/options//skew?expiry=undefined&date=undefined' \
--header 'x-api-key: ABCD314159'{
"data": {
"symbol": "SPY",
"snapshot_date": "string",
"underlier_price": 0,
"expiry": "string",
"atm_iv": 0,
"iv_call_25d": 0,
"iv_put_25d": 0,
"skew_25d": 0,
"call_25d_source": "string",
"put_25d_source": "string",
"contracts_used_calls": 0,
"contracts_used_puts": 0,
"dropped_unreliable_iv": 0,
"dropped_missing_delta": 0
},
"meta": {
"endpoint": "/api/v1/fred/us/cpi",
"data_time": "2026-04-16T14:30:00Z",
"response_time": "2026-04-16T14:30:12Z",
"provider": "Sugra API v1.0.1",
"data_age_days": 0,
"source": "string",
"attribution": "string",
"fallback_used": true,
"fallback_chain": [
"string"
],
"cached": true,
"stale": true,
"stale_since": "string",
"period": "string",
"notes": "string"
}
}