Real-time Options Gamma Exposure Profiler
Gexify is a web tool for options traders that fetches live options chain data, calculates Gamma Exposure (GEX) per strike using the Black-Scholes model, and visualizes them as interactive charts — helping you identify key support, resistance, flip levels, and market volatility regimes.
- Live GEX Chart — Bar chart of Call GEX (positive) vs Put GEX (negative) per strike, filtered to the closest ±20 strikes from spot for optimal clarity
- Spot Price Line — Dashed white vertical line marking the current price on the chart
- GEX Flip Level — Cumulative GEX zero-crossing strike (dealer gamma reversal); shown as an orange dashed line + badge
- Support & Resistance Detection — Auto-identifies the peak put GEX strike (support) and peak call GEX strike (resistance)
- Market Regime Insight — Positive GEX (low vol / range-bound) or Negative GEX (high vol / directional) signal
- Term Structure Timeline — Swap the view to plot GEX by expiration date, automatically surfacing the dominant strike for each date directly in the tooltips
- Term Structure Heatmap — Expiration dropdown dynamically colors dates with Emojis (🔴/🟢) and displays exact Net GEX values in Billions, giving an instant macro-view of the options flow
- Auto-Refresh Toggle — Keeps the dashboard live by silently polling background data every 60 seconds
- Async Backend — yfinance calls run in a thread pool executor so the FastAPI event loop is never blocked
- Robust Error Handling & Validation — Strict regex ticker validation, detailed API error messages, and graceful handling of closed-market periods
- Fast In-Memory Caching — Uses
TTLCacheto store expensive option chains for 60 seconds, preventing Yahoo Finance rate limits and dropping API response times to 0.02s - Vectorized Math Engine — Uses pure
numpybroadcasting to compute Black-Scholes Greeks across the entire options chain natively, optimizing computation times for multi-date views - Dark Glassmorphism UI — Clean, modern dark-mode interface built with vanilla JS + CSS featuring smooth fade-in animations
Uses Black-Scholes Gamma, scaled to dollar exposure:
GEX per strike:
Γ = N'(d1) / (S × σ × √T)
Call GEX = Γ × OI × 100 × Spot
Put GEX = Γ × OI × 100 × Spot × (−1) ← negative by convention
where:
d1 = [ln(S/K) + (r + 0.5σ²)T] / (σ√T)
S = Spot Price | K = Strike | T = Time to expiry (years)
r = Risk-free rate (4%) | σ = Implied Volatility
OI = Open Interest | 100 = standard US contract multiplier
GEX flip level is computed by sorting strikes, taking the cumulative sum of Total GEX, and finding the first strike where the running total changes sign.
gexify/
├── app/
│ ├── main.py # FastAPI app setup, CORS, static mount
│ ├── api/
│ │ └── endpoints.py # API routes (async executor wrappers)
│ ├── models/
│ │ └── gex.py # Pydantic models: GexDataPoint, GexResponse
│ └── services/
│ └── gex_calculator.py # Black-Scholes gamma + yfinance pipeline
├── static/
│ ├── index.html # Single-page frontend
│ ├── app.js # Chart.js rendering + sparkline
│ └── styles.css # Dark glassmorphism theme
├── pyproject.toml # Python dependencies (uv)
└── main.py # Root entry point
- Python 3.13+
uvpackage manager
# Clone the repo
git clone https://github.com/vikbht/gexify.git
cd gexify
# Install dependencies
uv sync
# Start the server
uv run uvicorn app.main:app --reloadThen open http://localhost:8000 in your browser.
| Method | Endpoint | Description |
|---|---|---|
GET |
/api/gex/{ticker}/expirations |
List available options expiration dates with net GEX |
GET |
/api/gex/{ticker} |
Returns GEX profiles. Query params: view_mode (single, term_structure, total) and expiration |
| Layer | Technology |
|---|---|
| Backend | FastAPI, Uvicorn |
| Data | yfinance, pandas, numpy, scipy |
| Models | Pydantic v2 |
| Frontend | Vanilla JS, Chart.js |
| Styling | Vanilla CSS (Glassmorphism) |
| Package Mgmt | uv |
| Signal | Meaning |
|---|---|
| 🟢 Positive GEX (green bars) | Call gamma — dealers hedge by selling rallies (suppresses upside) |
| 🔴 Negative GEX (red bars) | Put gamma — dealers hedge by buying dips (amplifies downside) |
| Dashed white line | Current spot price |
| Dashed orange line | GEX flip level — cumulative gamma changes sign here |
| Support badge | Strike with the largest put GEX concentration |
| Resistance badge | Strike with the largest call GEX concentration |
| GEX Flip badge | Where cumulative GEX = 0; below spot → bearish lean, above → bullish |
| 🛡️ Positive GEX Regime | Total GEX > 0 → vol suppressed → range-bound / choppy |
| 🚀 Negative GEX Regime | Total GEX < 0 → vol amplified → expect large directional moves |
| ⏱️ Auto-Refresh Toggle | When enabled, silently updates the backend data every 60 seconds |
| 📅 Term Structure View | Toggling the Data Scope plots Expirations (X-axis) against Net GEX (Y-axis), revealing major OPEX walls |
| 📍 Dominant Strike Tooltip | Hovering over Term Structure bars reveals the specific strike anchoring that date's GEX concentration |
| 🔥 Term Structure Heatmap | Shows the Net GEX value in Billions for the next 30+ expiration dates in the dropdown |
This tool is for educational and informational purposes only. It does not constitute financial advice. Always do your own research before making any trading decisions.
{ "ticker": "SPY", "spot_price": 676.33, "expiration_date": "2026-03-25", "gex_data": [ { "strike": 675.0, "call_gex": 1.2e9, "put_gex": -0.8e9, "total_gex": 0.4e9, "date": "2026-03-25", // Included in Term Structure view "dom_call_strike": 680.0, // Highest call gamma strike (Term Structure) "dom_put_strike": 670.0 // Highest put gamma strike (Term Structure) } ], "historical_prices": [{ "date": "09:30", "price": 678.1 }], "gex_flip_strike": 637.0 }