Data types

One section per FlashAlpha endpoint family. Each section lists:

the endpoint slug and a link to the underlying API reference,
the C# and Python bar class names,
the field table (every property declared on the bar),
a representative truncated JSON response,
a side-by-side OnData example.

For top-down navigation jump to the catalog in README.md. For the API-cost-per-resolution table see getting-started.md.

Field tables use these conventions:

Nullable — Yes means the property is declared as T? (C#) or Optional[T] (Python) on the bar; null-check before drilling in.
Type — the C# type. Python equivalents follow the obvious mapping (double? → Optional[float], string? → str defaulting to "", List<X>? → Optional[List[Any]], nested object → Optional[Dict[str, Any]] in Python / typed SDK model in C#).
Wire-format quirks (e.g. JSON key not snake_case) are called out under the field table.

GEX — gamma exposure
DEX — delta exposure
VEX — vanna exposure
CHEX — charm exposure
Exposure summary
Exposure levels
Vol surface
Zero-DTE
Max pain
Volatility
Advanced volatility
VRP — variance risk premium
Narrative
Stock summary
Stock quote
Option quote
Tickers (coverage)

GEX — gamma exposure

Endpoint: exposure/gex
C# class: FlashAlphaGexBar
Python class: GexBar
Sugar: algo.AddFlashAlphaGex("SPY") / add_flashalpha_gex(self, "SPY")

Strike-by-strike net dealer gamma exposure with the headline net GEX, the gamma flip strike, and a coarse "positive" / "negative" regime label.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	Ticker echoed by the API (JSON key `symbol`). LEAN's `Symbol` lives on `BaseData`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	Server-side timestamp the row was resolved at (ISO-8601).	Yes
`GammaFlip`	`double`	Strike where net dealer gamma crosses zero. `null` when no zero crossing exists.	Yes
`NetGex`	`double`	Net dealer gamma exposure, dollars per 1% spot move.	Yes
`NetGexLabel`	`string`	Coarse label — typically `"positive"` / `"negative"`.	Yes
`Strikes`	`List<GexStrikeRow>`	Per-strike GEX table. Each row carries `Strike`, `CallGex`, `PutGex`, `NetGex`, `CallOi`, `PutOi`, `CallOiChange`, `PutOiChange`. Per-row `CallVolume` / `PutVolume` are placeholders on historical.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "gamma_flip": 475.0,
  "net_gex": 1845231231.4,
  "net_gex_label": "positive",
  "strikes": [
    {"strike": 470.0, "call_gex": 81231.2, "put_gex": -213213.0, "net_gex": -132000.0,
     "call_oi": 18200, "put_oi": 24310, "call_oi_change": 1200, "put_oi_change": -300},
    {"strike": 475.0, "call_gex": 142123.1, "put_gex": -141900.2, "net_gex": 222.9,
     "call_oi": 24100, "put_oi": 23800, "call_oi_change": 800, "put_oi_change": 200}
  ]
}

Reading the bar

public override void OnData(Slice slice)
{
    var bar = slice.Get<FlashAlphaGexBar>(_gex);
    if (bar == null) return;
    Debug($"net_gex={bar.NetGex:F0}  label={bar.NetGexLabel}  flip={bar.GammaFlip:F2}");

    if (bar.Strikes != null)
        foreach (var row in bar.Strikes)
            Debug($"  K={row.Strike:F2}  net={row.NetGex:F0}  callOI={row.CallOi}");
}

Python

def OnData(self, slice):
    if self.gex not in slice:
        return
    bar = slice[self.gex]
    self.Debug(f"net_gex={bar.NetGex:.0f}  label={bar.NetGexLabel}  flip={bar.GammaFlip:.2f}")

    for row in (bar.Strikes or []):
        self.Debug(f"  K={row['strike']:.2f}  net={row['net_gex']:.0f}  callOI={row['call_oi']}")

DEX — delta exposure

Endpoint: exposure/dex
C# class: FlashAlphaDexBar
Python class: DexBar
Sugar: algo.AddFlashAlphaDex("SPY") / add_flashalpha_dex(self, "SPY")

Net dealer delta exposure across the chain. Same shape as GEX minus the gamma-flip / label fields — directionally read off NetDex for whether dealers are net long or net short the underlier.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`NetDex`	`double`	Net dealer delta exposure (dollars).	Yes
`Strikes`	`List<DexStrikeRow>`	Per-strike DEX table.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "net_dex": -123421000.0,
  "strikes": [
    {"strike": 470.0, "call_dex": 32100.0, "put_dex": -54000.0, "net_dex": -21900.0,
     "call_oi": 18200, "put_oi": 24310}
  ]
}

Reading the bar

var bar = slice.Get<FlashAlphaDexBar>(_dex);
if (bar == null) return;
Debug($"net_dex={bar.NetDex:F0}");

Python

bar = slice[self.dex]
self.Debug(f"net_dex={bar.NetDex:.0f}")

VEX — vanna exposure

Endpoint: exposure/vex
C# class: FlashAlphaVexBar
Python class: VexBar
Sugar: algo.AddFlashAlphaVex("SPY") / add_flashalpha_vex(self, "SPY")

Net dealer vanna exposure (∂delta/∂vol). Includes a hand-tuned VexInterpretation string that explains the vol-spot linkage in English.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`NetVex`	`double`	Headline net dealer vanna exposure.	Yes
`VexInterpretation`	`string`	Plain-English explanation of the regime. Safe to surface verbatim.	Yes
`Strikes`	`List<VexStrikeRow>`	Per-strike VEX table.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "net_vex": 4123121.0,
  "vex_interpretation": "Dealers are long vanna — falling IV likely supports spot.",
  "strikes": [...]
}

Reading the bar

var bar = slice.Get<FlashAlphaVexBar>(_vex);
if (bar?.VexInterpretation != null) Debug(bar.VexInterpretation);

Python

bar = slice[self.vex]
if bar.VexInterpretation:
    self.Debug(bar.VexInterpretation)

CHEX — charm exposure

Endpoint: exposure/chex
C# class: FlashAlphaChexBar
Python class: ChexBar
Sugar: algo.AddFlashAlphaChex("SPY") / add_flashalpha_chex(self, "SPY")

Net dealer charm exposure (∂delta/∂time) — directional delta drift as time passes. ChexInterpretation explains the regime.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`NetChex`	`double`	Headline net dealer charm exposure.	Yes
`ChexInterpretation`	`string`	Plain-English explanation of the regime.	Yes
`Strikes`	`List<ChexStrikeRow>`	Per-strike CHEX table.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "net_chex": -812000.0,
  "chex_interpretation": "Dealer delta drifts short as the day decays — supports a fade.",
  "strikes": [...]
}

Reading the bar

var bar = slice.Get<FlashAlphaChexBar>(_chex);
if (bar == null) return;
Debug($"net_chex={bar.NetChex:F0}");

Python

bar = slice[self.chex]
self.Debug(f"net_chex={bar.NetChex:.0f}")

Exposure summary

Endpoint: exposure/summary
C# class: FlashAlphaExposureSummaryBar
Python class: ExposureSummaryBar
Sugar: algo.AddFlashAlphaExposureSummary("SPY") / add_flashalpha_exposure_summary(self, "SPY")

The roll-up of GEX/DEX/VEX/CHEX into a single response with an English Regime label, HedgingEstimate for ±1% spot moves, and a 0DTE contribution block. Use this when you only need the headline — one call vs four.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`GammaFlip`	`double`	Strike where net dealer gamma crosses zero.	Yes
`Regime`	`string`	One of `"positive_gamma"`, `"negative_gamma"`, or `"unknown"`.	Yes
`Exposures`	`ExposureSummaryExposures` / `dict`	Net totals across the chain.	Yes
`Interpretation`	`ExposureSummaryInterpretation` / `dict`	Verbal interpretation of the gamma/vanna/charm regimes.	Yes
`HedgingEstimate`	`ExposureSummaryHedgingEstimate` / `dict`	Estimated dealer hedging flow at ±1% spot moves.	Yes
`ZeroDte`	`ExposureSummaryZeroDte` / `dict`	Same-day-expiration contribution to total GEX.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "gamma_flip": 475.0,
  "regime": "positive_gamma",
  "exposures": {"net_gex": 1845231231.4, "net_dex": -123421000.0, "net_vex": 4123121.0, "net_chex": -812000.0},
  "interpretation": {"gamma": "Dealers long gamma; expect mean reversion.", "vanna": "...", "charm": "..."},
  "hedging_estimate": {"up_1pct": -42000000.0, "down_1pct": 51000000.0},
  "zero_dte": {"gex_share": 0.18}
}

Reading the bar

var bar = slice.Get<FlashAlphaExposureSummaryBar>(_summary);
if (bar?.Exposures == null) return;
Debug($"regime={bar.Regime}  net_gex={bar.Exposures.NetGex:F0}  hedging↑1%={bar.HedgingEstimate?.Up1pct:F0}");

Python

bar = slice[self.summary]
ex = bar.Exposures or {}
hedge = bar.HedgingEstimate or {}
self.Debug(f"regime={bar.Regime}  net_gex={ex.get('net_gex'):.0f}  hedging↑1%={hedge.get('up_1pct'):.0f}")

Exposure levels

Endpoint: exposure/levels
C# class: FlashAlphaExposureLevelsBar
Python class: ExposureLevelsBar
Sugar: algo.AddFlashAlphaExposureLevels("SPY") / add_flashalpha_exposure_levels(self, "SPY")

The distilled set of dealer-flow key levels — gamma flip, call wall, put wall, max GEX strike, magnet, etc. Skip the per-strike detail and read the trade-able levels directly.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`Levels`	`ExposureLevels` / `dict`	Key levels block — drill in for `gamma_flip`, `call_wall`, `put_wall`, etc.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "levels": {
    "gamma_flip": 475.0,
    "call_wall": 480.0,
    "put_wall": 470.0,
    "max_gex_strike": 478.0,
    "magnet": 477.5
  }
}

Reading the bar

var bar = slice.Get<FlashAlphaExposureLevelsBar>(_levels);
if (bar?.Levels == null) return;
Debug($"flip={bar.Levels.GammaFlip:F2}  callWall={bar.Levels.CallWall:F2}  putWall={bar.Levels.PutWall:F2}");

Python

bar = slice[self.levels]
lv = bar.Levels or {}
self.Debug(f"flip={lv.get('gamma_flip')}  callWall={lv.get('call_wall')}  putWall={lv.get('put_wall')}")

Vol surface

Endpoint: surface
C# class: FlashAlphaSurfaceBar
Python class: SurfaceBar
Sugar: algo.AddFlashAlphaSurface("SPY") / add_flashalpha_surface(self, "SPY")

A smoothed implied-vol surface — a tenor × moneyness grid of IVs. Walk the grid or interpolate at an arbitrary point.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`Spot`	`double`	Spot price at `AsOf` (note: JSON key is `spot`, not `underlying_price`).	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`GridSize`	`int`	Side length — both `Tenors` and `Moneyness` have this many entries.	Yes
`Tenors`	`double[]`	Tenor values (years) — rows of `Iv`.	Yes
`Moneyness`	`double[]`	Moneyness values — columns of `Iv`.	Yes
`Iv`	`double[][]`	IV grid. `Iv[tenorIndex][moneynessIndex]`. Annualised, percent.	Yes
`SlicesUsed`	`List<string>`	Expirations that contributed to the smoothed surface.	Yes

Sample response

{
  "symbol": "SPY",
  "spot": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "grid_size": 5,
  "tenors": [0.02, 0.08, 0.25, 0.5, 1.0],
  "moneyness": [0.9, 0.95, 1.0, 1.05, 1.1],
  "iv": [
    [0.34, 0.27, 0.18, 0.15, 0.21],
    [0.31, 0.24, 0.17, 0.16, 0.20],
    [0.28, 0.22, 0.16, 0.17, 0.21]
  ],
  "slices_used": ["2024-06-17", "2024-06-21", "2024-07-19"]
}

Reading the bar

var bar = slice.Get<FlashAlphaSurfaceBar>(_surface);
if (bar?.Iv == null) return;
// ATM at the front tenor:
var atmFront = bar.Iv[0][bar.Moneyness!.Length / 2];
Debug($"front ATM IV={atmFront:F3}");

Python

bar = slice[self.surface]
if not bar.Iv:
    return
atm_front = bar.Iv[0][len(bar.Moneyness) // 2]
self.Debug(f"front ATM IV={atm_front:.3f}")

There's an interpolation recipe in docs/recipes/vol-surface-snapshot-in-quantconnect.md.

Zero-DTE

Endpoint: exposure/zero-dte
C# class: FlashAlphaZeroDteBar
Python class: ZeroDteBar
Sugar: algo.AddFlashAlphaZeroDte("SPY") / add_flashalpha_zero_dte(self, "SPY")

The single richest bar in the bridge. Same-day-expiry dealer positioning: regime, exposures, expected move, pin risk, hedging flows, decay, vol context, flow, key levels, liquidity, plus per-strike breakdown. On names with no same-day expiry the bar arrives "thin" — NoZeroDte = true, all nested blocks null, NextZeroDteExpiry pointing forward.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`Expiration`	`string`	Same-day expiration date (YYYY-MM-DD).	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`MarketOpen`	`bool`	`true` when resolved during the US-equity session.	Yes
`TimeToCloseHours`	`double`	Hours remaining until cash close.	Yes
`TimeToClosePct`	`double`	Fraction of session ahead — 1.0 at open, 0.0 at close.	Yes
`Regime`	`ZeroDteRegime` / `dict`	Regime label + gamma-flip context.	Yes
`Exposures`	`ZeroDteExposures` / `dict`	0DTE net Greek exposures plus share-of-total-chain GEX.	Yes
`ExpectedMove`	`ZeroDteExpectedMove` / `dict`	Implied 1-sigma move (full session, remaining) and ATM IV.	Yes
`PinRisk`	`ZeroDtePinRisk` / `dict`	Magnet strike, pin score, component breakdown.	Yes
`Hedging`	`ZeroDteHedging` / `dict`	Dealer hedging flow estimates across a grid of spot moves.	Yes
`Decay`	`ZeroDteDecay` / `dict`	Theta and charm regime for the remaining session.	Yes
`VolContext`	`ZeroDteVolContext` / `dict`	0DTE vs 7DTE ATM IV, VIX, vanna exposure.	Yes
`Flow`	`ZeroDteFlow` / `dict`	0DTE volume / OI breakdown and put-call ratios.	Yes
`Levels`	`ZeroDteLevels` / `dict`	0DTE-specific dealer-flow key levels.	Yes
`Liquidity`	`ZeroDteLiquidity` / `dict`	Spread + execution-score liquidity metrics.	Yes
`Metadata`	`ZeroDteMetadata` / `dict`	Snapshot age and data-quality scores.	Yes
`Strikes`	`List<ZeroDteStrike>`	Per-strike 0DTE breakdown — full Greek + flow snapshot.	Yes
`Warnings`	`List<string>`	Non-fatal warnings the engine emitted.	Yes
`NoZeroDte`	`bool`	`true` when no same-day expiry exists for the ticker.	Yes
`Message`	`string`	Human-readable message accompanying a "no zero-DTE" response.	Yes
`NextZeroDteExpiry`	`string`	Next available expiry when `NoZeroDte` is `true`.	Yes

Sample response (populated)

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "expiration": "2024-06-14",
  "as_of": "2024-06-14T17:00:00Z",
  "market_open": true,
  "time_to_close_hours": 3.0,
  "time_to_close_pct": 0.46,
  "regime": {"label": "positive_gamma", "gamma_flip": 477.5},
  "pin_risk": {"score": 72, "magnet_strike": 478.0, "components": {"gex": 0.4, "oi": 0.3, "distance": 0.3}},
  "expected_move": {"sigma_full": 4.1, "sigma_remaining": 2.0, "atm_iv": 0.12},
  ...
}

Sample response (thin)

{
  "symbol": "AAPL",
  "no_zero_dte": true,
  "message": "AAPL does not have a same-day expiration; next is 2024-06-21.",
  "next_zero_dte_expiry": "2024-06-21"
}

Reading the bar

var bar = slice.Get<FlashAlphaZeroDteBar>(_zdte);
if (bar == null) return;
if (bar.NoZeroDte == true) { Debug($"no 0DTE — next {bar.NextZeroDteExpiry}"); return; }
Debug($"pin_score={bar.PinRisk?.Score}  magnet={bar.PinRisk?.MagnetStrike:F2}");

Python

bar = slice[self.zdte]
if bar.NoZeroDte:
    self.Debug(f"no 0DTE — next {bar.NextZeroDteExpiry}")
    return
pr = bar.PinRisk or {}
self.Debug(f"pin_score={pr.get('score')}  magnet={pr.get('magnet_strike')}")

Full pin-risk recipe: docs/recipes/0dte-pin-risk-check-in-quantconnect.md.

Max pain

Endpoint: max-pain
C# class: FlashAlphaMaxPainBar
Python class: MaxPainBar
Sugar: algo.AddFlashAlphaMaxPain("SPY") / add_flashalpha_max_pain(self, "SPY")

The strike that minimizes aggregate option-writer pain, plus distance-to-spot, dealer-wall alignment, pin probability score, expected move check, and the full pain curve.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`MaxPainStrike`	`double`	Strike where total writer pain is minimized.	Yes
`Distance`	`MaxPainDistance` / `dict`	Distance spot → pain (absolute, percent, direction).	Yes
`Signal`	`string`	Coarse pin/magnet signal (e.g. `"pin"`, `"gravitate"`).	Yes
`Expiration`	`string`	Single-expiry mode: the expiration. Null when `MaxPainByExpiration` is set.	Yes
`PutCallOiRatio`	`double`	Put OI ÷ call OI across the request's expiry scope.	Yes
`PainCurve`	`List<MaxPainCurveRow>`	Strike-by-strike pain curve. Minimum is at `MaxPainStrike`.	Yes
`OiByStrike`	`List<MaxPainOiRow>`	Per-strike OI + volume breakdown.	Yes
`MaxPainByExpiration`	`List<MaxPainByExpirationRow>`	Roll-up-all-expiries mode: one row per expiry. Null when `Expiration` is set.	Yes
`DealerAlignment`	`MaxPainDealerAlignment` / `dict`	Whether dealer-flow walls align with the pain strike.	Yes
`Regime`	`string`	Coarse regime (e.g. `"calm"`, `"trending"`).	Yes
`ExpectedMove`	`MaxPainExpectedMove` / `dict`	Expected-move bounds and whether pain falls inside them.	Yes
`PinProbability`	`int`	Composite 0-100 score for the likelihood spot pins.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "max_pain_strike": 477.0,
  "distance": {"abs": 1.21, "pct": 0.0025, "direction": "below"},
  "signal": "gravitate",
  "expiration": "2024-06-21",
  "put_call_oi_ratio": 1.14,
  "regime": "calm",
  "pin_probability": 64,
  "pain_curve": [{"strike": 470.0, "pain": 18200000.0}, ...]
}

Reading the bar

var bar = slice.Get<FlashAlphaMaxPainBar>(_mp);
if (bar == null) return;
Debug($"pain={bar.MaxPainStrike:F2}  prob={bar.PinProbability}  signal={bar.Signal}");

Python

bar = slice[self.mp]
self.Debug(f"pain={bar.MaxPainStrike:.2f}  prob={bar.PinProbability}  signal={bar.Signal}")

Volatility

Endpoint: volatility
C# class: FlashAlphaVolatilityBar
Python class: VolatilityBar
Sugar: algo.AddFlashAlphaVolatility("SPY") / add_flashalpha_volatility(self, "SPY")

The full volatility analytics block: realized vol ladder, IV-RV spreads, per-expiry skew profiles, term structure, IV dispersion, GEX/theta by DTE, put-call profile, OI concentration, hedging scenarios, and liquidity.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`MarketOpen`	`bool`	`true` when resolved during the US-equity session.	Yes
`RealizedVol`	`VolatilityRealizedVol` / `dict`	5d / 10d / 20d / 30d / 60d realized vol (annualised %).	Yes
`AtmIv`	`double`	At-the-money implied volatility (annualised %). Top-level scalar, not under `IvRvSpreads`.	Yes
`IvRvSpreads`	`VolatilityIvRvSpreads` / `dict`	IV-RV spreads across 5d / 10d / 20d / 30d horizons.	Yes
`SkewProfiles`	`List<VolatilitySkewProfile>`	Per-expiry skew: 10Δ / 25Δ wings, ATM, smile ratio, tail convexity.	Yes
`TermStructure`	`VolatilityTermStructure` / `dict`	Near vs far slope, contango/backwardation state.	Yes
`IvDispersion`	`VolatilityIvDispersion` / `dict`	IV dispersion across expiries and strikes.	Yes
`GexByDte`	`List<VolatilityGexByDte>`	Net dealer GEX aggregated by DTE bucket.	Yes
`ThetaByDte`	`List<VolatilityThetaByDte>`	Net option theta aggregated by DTE bucket.	Yes
`PutCallProfile`	`VolatilityPutCallProfile` / `dict`	By-expiry OI/volume ratios + by-moneyness OI breakdown.	Yes
`OiConcentration`	`VolatilityOiConcentration` / `dict`	Top-3/5/10% share + Herfindahl index.	Yes
`HedgingScenarios`	`List<VolatilityHedgingScenario>`	Projected dealer rebalance + notional at ±X% spot moves.	Yes
`Liquidity`	`VolatilityLiquidity` / `dict`	Bid-ask liquidity at ATM and wing regions.	Yes

Sample response

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "market_open": false,
  "realized_vol": {"rv_5d": 0.082, "rv_10d": 0.094, "rv_20d": 0.103, "rv_30d": 0.108, "rv_60d": 0.114},
  "atm_iv": 0.121,
  "iv_rv_spreads": {"vrp_5d": 0.039, "vrp_10d": 0.027, ...},
  "term_structure": {"slope": 0.012, "state": "contango"}
}

Reading the bar

var bar = slice.Get<FlashAlphaVolatilityBar>(_vol);
if (bar == null) return;
Debug($"atm_iv={bar.AtmIv:F3}  rv_20d={bar.RealizedVol?.Rv20d:F3}");

Python

bar = slice[self.vol]
rv = bar.RealizedVol or {}
self.Debug(f"atm_iv={bar.AtmIv:.3f}  rv_20d={rv.get('rv_20d'):.3f}")

Advanced volatility

Endpoint: adv-volatility
C# class: FlashAlphaAdvVolatilityBar
Python class: AdvVolatilityBar
Sugar: algo.AddFlashAlphaAdvVolatility("SPY") / add_flashalpha_adv_volatility(self, "SPY")

Per-expiry SVI parameters, forward prices, the full total-variance surface (log-moneyness × tenor grid), arbitrage flags, variance-swap fair values, and second-/third-order Greek surfaces.

Plan tier: Alpha or above. Cold-cache latency: ~1.5s — bump HttpTimeout if you see timeouts.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`MarketOpen`	`bool`	`true` during the US-equity session.	Yes
`SviParameters`	`List<AdvVolatilitySviParams>`	Per-expiry SVI: (a, b, ρ, m, σ) + forward + ATM total variance.	Yes
`ForwardPrices`	`List<AdvVolatilityForwardPrice>`	Per-expiry forward prices and basis vs spot.	Yes
`TotalVarianceSurface`	`AdvVolatilityVarianceSurface` / `dict`	Log-moneyness × tenor grid + implied-vol grid.	Yes
`ArbitrageFlags`	`List<AdvVolatilityArbitrageFlag>`	Detected butterfly / calendar arbitrage violations.	Yes
`VarianceSwapFairValues`	`List<AdvVolatilityVarianceSwap>`	Variance-swap fair values per expiry, with convexity adjustment.	Yes
`GreeksSurfaces`	`AdvVolatilityGreeksSurfaces` / `dict`	Second-/third-order greek surfaces (vanna, charm, volga, speed).	Yes

Sample response (truncated)

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "svi_parameters": [
    {"expiry": "2024-06-21", "a": 0.0034, "b": 0.082, "rho": -0.41, "m": -0.02, "sigma": 0.12,
     "forward": 478.4, "atm_total_variance": 0.0021}
  ],
  "arbitrage_flags": [],
  "variance_swap_fair_values": [{"expiry": "2024-06-21", "fair_value": 0.119, "convexity_adj": 0.004}]
}

Reading the bar

var bar = slice.Get<FlashAlphaAdvVolatilityBar>(_advvol);
if (bar?.SviParameters == null) return;
foreach (var p in bar.SviParameters)
    Debug($"  {p.Expiry}  forward={p.Forward:F2}  atm_var={p.AtmTotalVariance:F4}");

Python

bar = slice[self.advvol]
for p in (bar.SviParameters or []):
    self.Debug(f"  {p['expiry']}  forward={p['forward']:.2f}  atm_var={p['atm_total_variance']:.4f}")

VRP — variance risk premium

Endpoint: vrp
C# class: FlashAlphaVrpBar
Python class: VrpBar
Sugar: algo.AddFlashAlphaVrp("SPY") / add_flashalpha_vrp(self, "SPY")

Variance-risk-premium analytics — the spread between implied and realized vol, conditioned on regime, with strategy suitability scores. Plan tier: Alpha or above.

Common silent-null traps:

ZScore / Percentile live on Vrp, not the top level.
NetGex lives on Regime, not the top level.
HarvestScore (top-level concept in the docs) is GexConditioned.HarvestScore; NetHarvestScore is a separate composite.
StrategyScores and NetHarvestScore can be null on early historical timestamps — check Warnings.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	ISO-8601 timestamp.	Yes
`MarketOpen`	`bool`	`true` during the US-equity session.	Yes
`Vrp`	`VrpCore` / `dict`	Core VRP metrics block. `ZScore` / `Percentile` live here.	Yes
`VarianceRiskPremium`	`double`	Headline VRP scalar.	Yes
`ConvexityPremium`	`double`	Convexity premium.	Yes
`FairVol`	`double`	Fair-vol estimate.	Yes
`Directional`	`VrpDirectional` / `dict`	Directional VRP skew (downside/upside wings).	Yes
`TermVrp`	`List<VrpTermItem>`	VRP term structure — one row per DTE bucket.	Yes
`GexConditioned`	`VrpGexConditioned` / `dict`	VRP harvest score conditioned on dealer-gamma regime.	Yes
`VannaConditioned`	`VrpVannaConditioned` / `dict`	VRP outlook conditioned on net dealer vanna.	Yes
`Regime`	`VrpRegime` / `dict`	Regime snapshot. `NetGex` lives here.	Yes
`StrategyScores`	`VrpStrategyScores` / `dict`	0-100 strategy suitability scores. Null on early historical timestamps.	Yes
`NetHarvestScore`	`int`	0-100 composite harvest signal. Null on early historical timestamps.	Yes
`DealerFlowRisk`	`int`	Dealer-flow risk score.	Yes
`Warnings`	`List<string>`	Server-side warnings about data quality. Always present (possibly empty).	Yes
`Macro`	`VrpMacro` / `dict`	Macro-context snapshot used to condition the VRP outlook.	Yes

Sample response (truncated)

{
  "symbol": "SPY",
  "as_of": "2024-06-14T20:00:00Z",
  "vrp": {"z_score": 0.62, "percentile": 78, "spread_20d": 0.027},
  "variance_risk_premium": 0.027,
  "regime": {"net_gex": 1845231231.4, "label": "positive_gamma"},
  "strategy_scores": {"short_straddle": 71, "iron_condor": 64, "short_vol": 68},
  "net_harvest_score": 67,
  "warnings": []
}

Reading the bar

var bar = slice.Get<FlashAlphaVrpBar>(_vrp);
if (bar == null) return;
var z = bar.Vrp?.ZScore;          // careful — ZScore is on Vrp, not the top level
var netGex = bar.Regime?.NetGex;  // NetGex is on Regime
Debug($"vrp={bar.VarianceRiskPremium:F3}  z={z:F2}  harvest={bar.NetHarvestScore}  netGex={netGex:F0}");

Python

bar = slice[self.vrp]
vrp = bar.Vrp or {}
regime = bar.Regime or {}
self.Debug(
    f"vrp={bar.VarianceRiskPremium:.3f}  z={vrp.get('z_score'):.2f}  "
    f"harvest={bar.NetHarvestScore}  netGex={regime.get('net_gex'):.0f}"
)

Narrative

Endpoint: narrative
C# class: FlashAlphaNarrativeBar
Python class: NarrativeBar
Sugar: algo.AddFlashAlphaNarrative("SPY") / add_flashalpha_narrative(self, "SPY")

A hand-tuned, numbers-aware prose summary of the day's dealer positioning — regime, GEX change, key levels, flow, vanna, charm, 0DTE, outlook — plus the raw numbers backing each sentence under Narrative.data. Useful as an LLM prompt context block or a human-readable log line.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`UnderlyingPrice`	`double`	Underlying spot at `AsOf`.	Yes
`AsOf`	`string`	UTC timestamp the API actually used — snapped to the available minute.	Yes
`Narrative`	`NarrativeBlock` / `dict`	Prose lines under keys `regime` / `gex_change` / `key_levels` / `flow` / `vanna` / `charm` / `zero_dte` / `outlook`, plus a `data` sub-block with the raw numbers.	Yes

Sample response (truncated)

{
  "symbol": "SPY",
  "underlying_price": 478.21,
  "as_of": "2024-06-14T20:00:00Z",
  "narrative": {
    "regime": "Dealers are net long $1.85B of gamma; expect mean-reverting tape.",
    "key_levels": "Gamma flip 475, call wall 480, put wall 470.",
    "outlook": "Calm session likely; pin score 72 around 478.",
    "data": {"net_gex": 1845231231, "gamma_flip": 475.0, "call_wall": 480.0, "put_wall": 470.0}
  }
}

Reading the bar

var bar = slice.Get<FlashAlphaNarrativeBar>(_narr);
if (bar?.Narrative == null) return;
Debug(bar.Narrative.Regime);
Debug(bar.Narrative.Outlook);

Python

bar = slice[self.narr]
n = bar.Narrative or {}
self.Debug(n.get("regime", ""))
self.Debug(n.get("outlook", ""))

Stock summary

Endpoint: stock/summary
C# class: FlashAlphaStockSummaryBar
Python class: StockSummaryBar
Sugar: algo.AddFlashAlphaStockSummary("SPY") / add_flashalpha_stock_summary(self, "SPY")

The "single best snapshot" composite endpoint — price + volatility + options flow + exposure + macro context. Use this when one bar should give you the whole picture for a name. Plan tier: Alpha or above.

Historical-specific gaps:

OptionsFlow.TotalCallVolume / TotalPutVolume / PcRatioVolume are always 0 / null (no minute volume on replay).
Macro.VixFutures is always null (CME futures aren't historically reconstructible from minute data).
Macro.FearAndGreed is always null (the CNN index isn't archived).

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `symbol`.	Yes
`AsOf`	`string`	UTC timestamp snapped to the available minute.	Yes
`MarketOpen`	`bool`	`true` during the US-equity session.	Yes
`PriceQuote`	`StockSummaryPrice` / `dict`	Top-of-book block: bid / ask / mid / last + last-update. Renamed from SDK `price` to avoid colliding with `BaseData.Price`.	Yes
`Volatility`	`StockSummaryVolatility` / `dict`	ATM IV, HV20/60, VRP, 25-delta skew, IV term structure.	Yes
`OptionsFlow`	`StockSummaryOptionsFlow` / `dict`	Aggregate options-flow stats — OI/volume by side + put-call ratios.	Yes
`Exposure`	`StockSummaryExposure` / `dict`	Dealer-exposure block — greeks, walls, gamma flip, max pain, hedging, 0DTE, top strikes.	Yes
`Macro`	`StockSummaryMacro` / `dict`	VIX / VVIX / SKEW / SPX / MOVE + term structure + fear-and-greed.	Yes

Sample response (truncated)

{
  "symbol": "SPY",
  "as_of": "2024-06-14T20:00:00Z",
  "market_open": false,
  "price": {"bid": 478.20, "ask": 478.22, "mid": 478.21, "last": 478.21, "last_update": "2024-06-14T19:59:57Z"},
  "volatility": {"atm_iv": 0.121, "hv_20": 0.103, "hv_60": 0.114, "vrp": 0.018, "skew_25d": 0.024},
  "exposure": {"net_gex": 1845231231.4, "gamma_flip": 475.0, "call_wall": 480.0, "put_wall": 470.0},
  "macro": {"vix": 12.4, "vvix": 78.2, "skew": 142.1, "vix_futures": null}
}

Reading the bar

var bar = slice.Get<FlashAlphaStockSummaryBar>(_sum);
if (bar == null) return;
var mid = bar.PriceQuote?.Mid;
var atmIv = bar.Volatility?.AtmIv;
var flip = bar.Exposure?.GammaFlip;
Debug($"mid={mid:F2}  atm_iv={atmIv:F3}  flip={flip:F2}");

Python

bar = slice[self.sum]
pq = bar.PriceQuote or {}
vol = bar.Volatility or {}
ex = bar.Exposure or {}
self.Debug(f"mid={pq.get('mid')}  atm_iv={vol.get('atm_iv')}  flip={ex.get('gamma_flip')}")

Stock quote

Endpoint: stock/quote
C# class: FlashAlphaStockQuoteBar
Python class: StockQuoteBar
Sugar: algo.AddFlashAlphaStockQuote("SPY") / add_flashalpha_stock_quote(self, "SPY")

Top-of-book bid / ask / mid / last for the underlier — useful as a sanity check against LEAN's equity book at the same timestamp.

Wire-format quirk: the root key is ticker (not symbol), and the timestamp field is camelCase lastUpdate (not last_update). Both are aliased on the bar — read bar.Ticker and bar.LastUpdate as normal.

Fields

Field	Type	Description	Nullable
`Ticker`	`string`	JSON `ticker` (not `symbol` on this endpoint).	Yes
`Bid`	`double`	Best bid for the underlier.	Yes
`Ask`	`double`	Best ask for the underlier.	Yes
`Mid`	`double`	(Bid + ask) / 2.	Yes
`Last`	`double`	Last trade price.	Yes
`LastUpdate`	`string`	Last quote/trade update timestamp. JSON key is camelCase `lastUpdate`.	Yes

Sample response

{
  "ticker": "SPY",
  "bid": 478.20,
  "ask": 478.22,
  "mid": 478.21,
  "last": 478.21,
  "lastUpdate": "2024-06-14T19:59:57Z"
}

Reading the bar

var bar = slice.Get<FlashAlphaStockQuoteBar>(_q);
if (bar == null) return;
Debug($"bid={bar.Bid:F2}  ask={bar.Ask:F2}  mid={bar.Mid:F2}");

Python

bar = slice[self.q]
self.Debug(f"bid={bar.Bid}  ask={bar.Ask}  mid={bar.Mid}")

Option quote

Endpoint: option/quote
C# class: FlashAlphaOptionQuoteBar
Python class: OptionQuoteBar
Sugar: algo.AddFlashAlphaOptionQuote("SPY") / add_flashalpha_option_quote(self, "SPY")

The full option chain at the requested minute — one row per contract with bid / ask / mid, IV variants (from-mid, from-bid, from-ask), every first- and second-order Greek, and OI.

Historical-specific gaps:

Per-row BidSize / AskSize are always 0 (minute table has no sizes).
Per-row Volume is always 0.
Per-row SviVol is always null with SviVolGated == "backtest_mode".

Reader override: the upstream JSON root is an array, not an object, so the bar bypasses the standard mapper and deserialises the array directly into Quotes.

Fields

Field	Type	Description	Nullable
`Quotes`	`List<OptionQuoteRow>`	The full option-chain array. Each row's fields are listed below.	Yes

`OptionQuoteRow` fields

Field	Type	Description	Nullable
`Type`	`string`	`"C"` or `"P"`.	Yes
`Expiry`	`string`	Expiration date (`yyyy-MM-dd`).	Yes
`Strike`	`double`		Yes
`Bid`	`double`		Yes
`Ask`	`double`		Yes
`Mid`	`double`	`(Bid + Ask) / 2`.	Yes
`BidSize`	`int`	Always 0 on historical.	Yes
`AskSize`	`int`	Always 0 on historical.	Yes
`LastUpdate`	`string`	JSON key is camelCase `lastUpdate`.	Yes
`Underlying`	`double`	Underlying mid price at the quote time.	Yes
`ImpliedVol`	`double`	IV inverted from the mid (annualised %).	Yes
`IvBid`	`double`	IV inverted from the bid.	Yes
`IvAsk`	`double`	IV inverted from the ask.	Yes
`Delta`	`double`		Yes
`Gamma`	`double`		Yes
`Theta`	`double`		Yes
`Vega`	`double`		Yes
`Rho`	`double`		Yes
`Vanna`	`double`	∂²V/∂S∂σ.	Yes
`Charm`	`double`	∂²V/∂S∂t.	Yes
`SviVol`	`double`	Always null on historical (`svi_vol_gated == "backtest_mode"`).	Yes
`SviVolGated`	`string`	Always `"backtest_mode"` on historical.	Yes
`OpenInterest`	`int`		Yes
`Volume`	`int`	Always 0 on historical.	Yes

Sample response (truncated)

[
  {"type": "C", "expiry": "2024-06-21", "strike": 480.0, "bid": 1.10, "ask": 1.12, "mid": 1.11,
   "implied_vol": 0.118, "delta": 0.42, "gamma": 0.083, "theta": -0.21, "vega": 0.31,
   "open_interest": 18200, "volume": 0, "svi_vol": null, "svi_vol_gated": "backtest_mode"},
  {"type": "P", "expiry": "2024-06-21", "strike": 480.0, "bid": 2.95, "ask": 2.98, "mid": 2.965,
   "delta": -0.58, "gamma": 0.083, "open_interest": 24310}
]

Reading the bar

var bar = slice.Get<FlashAlphaOptionQuoteBar>(_oq);
if (bar?.Quotes == null) return;
var atmCall = bar.Quotes.Find(q => q.Type == "C" && Math.Abs(q.Strike!.Value - 478.0) < 0.01);
if (atmCall != null) Debug($"ATM call mid={atmCall.Mid:F2}  delta={atmCall.Delta:F2}");

Python

bar = slice[self.oq]
if not bar.Quotes:
    return
atm_call = next(
    (q for q in bar.Quotes if q.get("type") == "C" and abs(q.get("strike", 0) - 478.0) < 0.01),
    None,
)
if atm_call:
    self.Debug(f"ATM call mid={atm_call['mid']}  delta={atm_call['delta']}")

Tickers (coverage)

Endpoint: tickers
C# class: FlashAlphaTickersBar + FlashAlphaTickersUniverse
Python class: TickersBar + FlashAlphaTickersUniverse
Sugar: algo.AddFlashAlphaTickers() / add_flashalpha_tickers(self)

The global coverage table — every supported symbol with first/last covered session and a healthy-day count. Use it standalone to introspect coverage, or wire FlashAlphaTickersUniverse to drive LEAN universe selection.

Special case: this is the only endpoint in the bridge that is not ticker-scoped. The bar still subscribes under a LEAN symbol (recommended sentinel: "_universe") but the HTTP layer ignores the ticker when the slug is "tickers".

Fields

Field	Type	Description	Nullable
`Tickers`	`List<TickersRow>`	Per-symbol coverage rows. Drive a universe selector.	Yes
`Count`	`int`	Length of `Tickers`.	Yes

Each TickersRow has a Symbol and a nested Coverage block with First, Last, and HealthyDays.

Sample response

{
  "count": 3,
  "tickers": [
    {"symbol": "SPY", "coverage": {"first": "2020-01-02", "last": "2024-06-14", "healthy_days": 1112}},
    {"symbol": "QQQ", "coverage": {"first": "2020-01-02", "last": "2024-06-14", "healthy_days": 1108}},
    {"symbol": "IWM", "coverage": {"first": "2020-01-02", "last": "2024-06-14", "healthy_days": 1095}}
  ]
}

Reading the bar

var bar = slice.Get<FlashAlphaTickersBar>(_tk);
if (bar?.Tickers == null) return;
foreach (var row in bar.Tickers)
    Debug($"  {row.Symbol}  healthy={row.Coverage?.HealthyDays}");

Python

bar = slice[self.tk]
for row in (bar.Tickers or []):
    cov = row.get("coverage", {})
    self.Debug(f"  {row.get('symbol')}  healthy={cov.get('healthy_days')}")

Driving a universe

// C#
public override void Initialize()
{
    AddUniverseSelection(new FlashAlphaTickersUniverse(
        row => (row.Coverage?.HealthyDays ?? 0) > 90));
}

# Python
def Initialize(self):
    self.AddUniverseSelection(FlashAlphaTickersUniverse(
        filter=lambda row: row.get("coverage", {}).get("healthy_days", 0) > 90
    ))

Full universe walkthrough: docs/recipes/filter-universe-by-gex-regime.md.

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data-types.md

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Data types

Contents

GEX — gamma exposure

Fields

Sample response

Reading the bar

DEX — delta exposure

Fields

Sample response

Reading the bar

VEX — vanna exposure

Fields

Sample response

Reading the bar

CHEX — charm exposure

Fields

Sample response

Reading the bar

Exposure summary

Fields

Sample response

Reading the bar

Exposure levels

Fields

Sample response

Reading the bar

Vol surface

Fields

Sample response

Reading the bar

Zero-DTE

Fields

Sample response (populated)

Sample response (thin)

Reading the bar

Max pain

Fields

Sample response

Reading the bar

Volatility

Fields

Sample response

Reading the bar

Advanced volatility

Fields

Sample response (truncated)

Reading the bar

VRP — variance risk premium

Fields

Sample response (truncated)

Reading the bar

Narrative

Fields

Sample response (truncated)

Reading the bar

Stock summary

Fields

Sample response (truncated)

Reading the bar

Stock quote

Fields

Sample response

Reading the bar

Option quote

Fields

OptionQuoteRow fields

Sample response (truncated)

Reading the bar

Tickers (coverage)

Fields

Sample response

Reading the bar

Driving a universe

`OptionQuoteRow` fields