{
  "pack_version": "2026-10-15",
  "description": "Saved current-engine replay responses, not live data or raw option-chain inputs.",
  "format_note": "JSON payloads are unchanged; line endings normalized to LF before hashing.",
  "request": {
    "base": "https://historical.flashalpha.com",
    "symbol": "SPY",
    "endpoints": {
      "gex": {
        "path": "/v1/exposure/gex/SPY",
        "parameters": {
          "at": "2026-03-05T15:30:00"
        },
        "expiration_scope": "All expirations"
      },
      "levels": {
        "path": "/v1/exposure/levels/SPY",
        "parameters": {
          "at": "2026-03-05T15:30:00"
        },
        "expiration_scope": "All expirations"
      }
    },
    "timezone": "America/New_York (Eastern wall-clock, no offset in at)",
    "equivalent_utc": "2026-03-05T20:30:00Z",
    "retrieval_note": "Original fixture capture time was not recorded. Pack updated 2026-10-15 from the site's published historical-samples; not a new authenticated request."
  },
  "sources": {
    "gex.json": "https://flashalpha.com/historical-samples/hist-gex.json",
    "levels.json": "https://flashalpha.com/historical-samples/hist-levels.json"
  },
  "expected": {
    "underlying_price": 679.46,
    "net_gex": -14504525330.202955,
    "gamma_flip": 687.171655677348,
    "levels": {
      "gamma_flip": 687.171655677348,
      "max_positive_gamma": 700,
      "max_negative_gamma": 680,
      "call_wall": 685,
      "put_wall": 675,
      "highest_oi_strike": 630,
      "zero_dte_magnet": 675
    },
    "endpoint_version": "2026.08.25",
    "strike_count": 439
  },
  "assumptions": [
    "Current engine applied to archived inputs; not JSON as served on March 5.",
    "Settled OI and fixed calls-positive / puts-negative structural exposure; no observed dealer inventory.",
    "GEX units: USD delta notional per 1% underlying move; equity contract multiplier 100.",
    "archive_as_of describes input vintage; data_as_of is null for historical live-feed slots.",
    "Saved payload predates newer flip-certification fields. Missing status does not certify a regime.",
    "Offline checks validate published response parsing and hashes, not the proprietary gamma engine or a strategy's profitability."
  ],
  "sha256": {
    "gex.json": "a6302ecd14779b4350f9e9dfae4998ed1418f9decb8607e03c9b1e7e7767b12e",
    "levels.json": "c95cb30805423bbae8a4ece96a0a42e41891b6dede9c73492c5883c0b4638eab"
  }
}