Flow GEX API

Endpoint

curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://lab.flashalpha.com/v1/flow/gex/SPY"

import requests

resp = requests.get(
    "https://lab.flashalpha.com/v1/flow/gex/SPY",
    headers={"X-Api-Key": "YOUR_API_KEY"}
)
data = resp.json()
print(f"Live net GEX: ${data['live_net_gex']:,.0f} ({data['live_net_gex_label']})")
print(f"Live gamma flip: {data['live_gamma_flip']}")

const resp = await fetch(
  "https://lab.flashalpha.com/v1/flow/gex/SPY",
  { headers: { "X-Api-Key": "YOUR_API_KEY" } }
);
const data = await resp.json();
console.log(`Live net GEX: $${data.live_net_gex.toLocaleString()} (${data.live_net_gex_label})`);
console.log(`Live gamma flip: ${data.live_gamma_flip}`);

Response

{
  "symbol": "SPY",
  "as_of": "2026-05-12T18:42:10Z",
  "underlying_price": 597.505,
  "expiry": "2026-05-15",
  "live_net_gex": 3120000000,
  "live_net_gex_label": "positive",
  "live_gamma_flip": 595.50,
  "strikes": [
    {
      "strike": 595.0,
      "call_gex": 13800000,
      "put_gex": 9600000,
      "net_gex": 23400000,
      "call_oi": 16200,
      "put_oi": 12700,
      "call_volume": 320,
      "put_volume": 240,
      "call_oi_change": 1200,
      "put_oi_change": -150
    }
  ]
}

Key Response Fields

About Flow GEX

Flow GEX is the live counterpart to /v1/exposure/gex. The settled endpoint uses morning OPRA-broadcast OI and stays frozen all session; this endpoint runs the exact same gamma-exposure math on the OI simulator's effective open interest, so the per-strike profile, net total, and gamma flip all drift intraday as positioning fills, exits, and rolls. Use it when you need a dealer-gamma snapshot that actually reflects mid-session reality.

Flow Polarity: Dealer-Position Signing

By default GEX is convention-signed (calls positive, puts negative), which describes the market's structural gamma but never says which side dealers are actually on. Add ?polarity=flow to sign each strike's gamma by the measured dealer position from quote-rule NBBO aggressor classification, Lee-Ready style (dealer_pos = sells − buys), so net_gex > 0 means dealers are net long gamma (pinning, volatility suppression) and net_gex < 0 means net short gamma (volatility amplification). Convention mode is Growth plan+; polarity=flow requires Alpha plan+. Omit the parameter and the response is unchanged.

curl -H "X-Api-Key: YOUR_API_KEY" \
  "https://lab.flashalpha.com/v1/flow/gex/SPY?polarity=flow"

In flow mode the response adds a top-level "polarity": "flow" plus the per-strike call_net_customer/put_net_customer (customer buys minus sells) and call_dealer_pos/put_dealer_pos (dealer inventory, -net_customer) diagnostics. Strikes with no classified trades contribute 0. It uses no open interest, no opening-fraction constant, and no decay heuristics, and it works historically via ?at=. Full explainer: flow-signed GEX: are dealers actually long or short gamma?

Common Use Cases

• Gate strategy on live_net_gex_label - switch to mean-reversion playbooks when it reads positive and trend/breakout playbooks when it flips negative, all on live effective OI rather than the morning snapshot
• Alert when live_gamma_flip crosses spot - diff the live flip strike against underlying_price and fire the moment dealers shift from dampening to amplifying moves
• Render a live GEX-by-strike heatmap - plot strikes[].net_gex across the chain to expose the walls and pockets that act as intraday support/resistance
• Size hedging pressure from live_net_gex - a larger absolute net GEX implies tighter dealer hedging and smaller realized ranges, so calibrate stops and targets to the magnitude
• Spot repositioning via call_oi_change / put_oi_change - per-strike day-over-day OI deltas reveal where new gamma is being built or unwound since the settled snapshot
• Diff against settled GEX - contrast per-strike call/put GEX with /v1/exposure/gex to quantify how far intraday flow has moved the dealer book

Related

Related reading

• Flow vs exposure endpoints: which GEX API to use - when to reach for live flow GEX vs the settled exposure endpoint
• Effective open interest: live GEX from flow - how the OI simulator produces the effective OI this endpoint runs on

Complementary endpoints

• Gamma Exposure (GEX) - the settled morning baseline to diff this live profile against
• Live Flow Levels - the flip and walls distilled out of this same live profile
• Flow Summary - a one-call digest of live positioning across the flow endpoints
• Live Flow DEX - directional dealer positioning to pair with live gamma