Strike Dependency API

Endpoint

curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://lab.flashalpha.com/v1/exposure/strike-dependency/SPY?strike=665"

import requests

resp = requests.get(
    "https://lab.flashalpha.com/v1/exposure/strike-dependency/SPY",
    headers={"X-Api-Key": "YOUR_API_KEY"},
    params={"strike": 665}
)
data = resp.json()
print(f"{data['dominant_expiry']} holds {data['dominant_expiry_share_pct']:.1f}% of the strike's gross gamma")

const resp = await fetch(
  "https://lab.flashalpha.com/v1/exposure/strike-dependency/SPY?strike=665",
  { headers: { "X-Api-Key": "YOUR_API_KEY" } }
);
const data = await resp.json();
console.log(data.dominant_expiry + " holds " + data.dominant_expiry_share_pct.toFixed(1) + "% of the strike gross gamma");

Response

{
  "symbol": "SPY",
  "underlying_price": 663.42,
  "analysis_type": "strike_attribution",
  "pricing_basis": "captured_cached_gamma_current_spot",
  "data_status": "partial",
  "strike": 665,
  "distance_from_spot_pct": 0.24,
  "gross_gex_usd": 610000000,
  "net_gex_usd": 140000000,
  "call_gex_usd": 375000000,
  "put_gex_usd": -235000000,
  "contract_count": 46,
  "by_expiry": [
    { "expiry": "2026-10-16", "calendar_days_to_expiry": 0,
      "gross_gex_usd": 290000000, "net_gex_usd": 90000000, "contract_count": 2,
      "share_of_strike_gross_pct": 47.54,
      "valuation_cutoff_at": "2026-10-16T20:00:00Z", "last_trading_at": "2026-10-16T20:15:00Z",
      "settlement_at": null, "settlement_status": "unknown" }
  ],
  "dominant_expiry": "2026-10-16",
  "dominant_expiry_share_pct": 47.54
}

Key Response Fields

Errors

About

A large gamma level can live almost entirely in one expiry. If that expiry rolls off, the level can fade even though nothing about the underlying changed. Strike dependency takes one exact observed strike and breaks its gross and net gamma exposure down by expiry, using the same captured inputs, eligibility rules and units as expiry impact.

The request is never snapped to a nearby strike: an absent strike returns 404 strike_not_found. The dominant expiry share describes concentration at that strike. It is not a support or resistance probability, and the calls-positive / puts-negative sign is a convention, not observed dealer inventory.

Replay the same view at a past minute on historical.flashalpha.com with at= (Alpha). Date-only at resolves to 15:55 ET so same-day Greeks stay defined. See historical trader context.

Common Use Cases

• Check a wall before expiry - see whether the call or put wall is mostly 0DTE or spread across the term
• Judge how durable a level is - a level held by several expiries survives one roll-off; a single-expiry level may not
• Explain a GEX change - compare the strike's expiry mix before and after OPEX
• Pair with expiry impact - find the strikes that lose the most gamma, then attribute each one

Related

Research

Call and put walls were tested on every 2022-2025 SPY and QQQ session. Once distance to the price was matched, walls held mostly by the expiring expiry did not break reliably more often than other walls.

• Does expiring gamma move the market? - results and method
• Research pack trader-context-spy-qqq-2022-2025-v2-34105d743fac - data, audit and reproduction (Alpha)

Related reading

• Call wall, put wall and gamma flip explained - how the levels are defined

Complementary endpoints

• Expiry Impact - the chain with one expiry excluded
• Key Levels - locate the walls to attribute
• Gamma Exposure (GEX) - strike-level GEX across the chain